Blood on the Forums XX - Mathematician’s Hell - Evil Wins - 3/10

Hmmm, that makes sense.

@Marluna

by the way, I still don’t really get how you came to the conclusion of Legion from Crazynuto’s Fisherman advice, could you explain?

i think mine was pretty fire

your mom is so fat assassin couldn’t kill her

I hardclaim autistic

2 Likes

Intensify has died!

1 Like

Joking

I wish I wasn’t

WORTH IT

1 Like

that reminds me of really good fisherman advice that was “you can take one of two of three sides”
which pointed straight at me as the demon because i knew that me, my minion, and the lunatic, were sat in a perfect equilateral triangle
and i tried to say “that makes no sense we should kill the fisherman”

1 Like

DON’T TELL THEM THAT

2 Likes

We were having a productive game relevant conversation

2 Likes

how do you dislike a post

image

2 Likes

In the last BotF I accidentally reported myself for spam because I meant to take a screenshot of the report menu as a joke

1 Like

TBF I posted all of Riichi Book One

this was also funny beucause i hardclaimed widow ping and artist publicly first thing d1
and my minion walks up to me and is like “im the widow and ive been bluffing artist”

at least they self-poisoned lmao

Summary

Riichi Book I
A Mahjong Strategy Primer
for European Players
Daina Chiba

Riichi Book I
A Mahjong Strategy Primer for European Players
Version 13
Daina Chiba
Copyright © 2016–2020 Daina Chiba.
Permission is granted to copy, distribute, and/or modify this document un-
der the terms of the Creative Commons Attribution NonCommercial 3.0
Unported License, available at Creative Commons — Attribution-NonCommercial 3.0 Unported — CC BY-NC 3.0.
Cover photo © 2015 Katarína Mózová, Courtesy of Riichi Mahjong Slovakia.
The original form of this book is LATEX source code. Compiling this LATEX
source has the effect of generating a device-independent representation of
a manuscript. The LATEX source for this book is available from https://
GitHub - dainachiba/RiichiBooks: A book on riichi mahjong strategies.
About the Author
Daina Chiba is a political scientist and an applied statistician working as a
lecturer at the University of Essex in England. He has been playing riichi
mahjong for almost 20 years. He can be reached at daina.chiba@gmail.com.
Preface
When I moved to England in 2013, I was pleasantly surprised to
learn that riichi mahjong (modern Japanese mahjong) is quite popu-
lar in Europe. In the past two years, I have had the pleasure of play-
ing riichi in London, Guildford, Kent, Oxford, Aachen, Copenhagen,
Prague, and Vienna, along with players from Austria, China, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Italy, Japan,
the Netherlands, Poland, Russia, Slovakia, Sweden, the UK, and the
United States.
European players have been remarkably successful in organizing
tournaments open to anyone who plays the game. These tourna-
ments — held at least once a month somewhere in Europe — are run
by local mahjong players in each country under the auspices of the
European Mahjong Association (EMA).1 Founded in 2005, EMA has
been doing a fantastic job in maintaining common rule sets,2 keep-
ing a player ranking system, and doing many other useful things to
promote the playing of mahjong across Europe.
Although I have come across a few good players in Europe, I came
to realize that a lot of players here are not very well-versed in the
basic principles of competitive mahjong strategies. Of course, play-
ing competitively is not the only way to enjoy the game. I am also
1 http://mahjong-europe.org/
2 EMA’s official rule book for riichi mahjong is available online at http:
//mahjong-europe.org/portal/images/docs/Riichi-rules-2016-EN.pdf
(last revised in 2016). At the time of writing this book, EMA is in the process
of revising the rule book. Explanations of EMA rules in this book are based on
the revised rules. New rules will come into effect from April, 2016.
iv PREFACE
not claiming that I know the magic formula to win because there is
no such thing. Nevertheless, there is a set of basic principles worth
learning for any aspiring players. I believe the level of sophistication
among European players could be much improved if these princi-
ples are more widely shared. Unfortunately, however, learning re-
sources currently available for non-Japanese audience are somewhat
limited.3
I have thus decided to write a book on riichi mahjong strategies
for European players, primarily with beginners and intermediate play-
ers in mind. I then ended up splitting the book into two volumes;
Book I is intended for beginners and intermediate players (Tenhou
rank of 四段 or below), while Book II is meant for more advanced
players. The two books are not intended for complete novices who
do not know how to play riichi mahjong.4 The target reader is any-
one who has played riichi mahjong before and wants to improve their
skills further.
I have three main goals in preparing these books. First, I will in-
troduce a set of English terminology of riichi mahjong. “In beginning
was Word,” scripture tells us. Knowing the names of particular tile
combinations, situations, and strategies will allow us to be conscious
of them and to be able to talk about them with our fellow players
after the game.
My second goal is to introduce the principles of tile efficiency.
Book I and Book II both cover tile efficiency, but at different levels.
3 There are already a few English books for beginners. There are also several
excellent blog posts on technical details about mahjong strategies. However,
there appears to be a huge gap between these two sets of resources. Introduc-
tory books do not cover strategies extensively, whereas blog posts tend to be
too advanced even for intermediate players.
4 If you want to learn how to play riichi, I’d recommend Barr (2009).
v
Book I offers an introduction to tile efficiency, covering very basic
mechanisms only. I plan to cover more advanced materials in Book
II. My third goal is to introduce a set of simple strategies regarding
critical judgements such as whether or not to call riichi, whether to
push or to fold, and whether or not to meld.
A lot of the materials covered in the books were introduced to
me through the writings of a notable Japanese mahjong player and
manga author, Masayuki Katayama. Mr. Katayama is an accomplished
riichi player and arguably the best mahjong manga author in the
world. Some of the strategies introduced here are unabashedly stolen
from Mr. Katayama’s masterpiece manga storybook U tahime Obaka-
miiko (『打姫オバカミーコ』). I strongly encourage you to read it
yourself if you read Japanese, although I realize that you would not
be reading my book if you understood Japanese.
Another Japanese author whose work has been influential in the
writing of Book I is Makoto Fukuchi. Mr. Fukuchi is also a distin-
guished riichi player and the best-selling author of mahjong strategy
books. A part of the exposition of the five-block method in Chapter
4 is based on Mr. Fukuchi’s skillful explanation in his books.
I am also indebted to a lot of friends I have become acquainted
with through mahjong in Europe. Philipp Martin has read an early
draft of the book and provided me with valuable comments and
encouragement. I am also grateful to Gemma Sakamoto, who has
been hosting a monthly mahjong get-together in London. Finally,
my thanks go to Ian Fraser, one of the founders of the UK Mahjong
Association. Without the efforts of Ian and his team, I would not
have been able to get to know so many fellow players in the UK and
in Europe.
vi PREFACE
The cover photo (© Katarína Mózová) is from the 2015 Bratislava
Riichi Open Tournament. I thank Katarína and Riichi Mahjong Slo-
vakia (especially Matej Labaš) for giving me their permission to use
it.
After I made the book publicly available in January 2016, a lot of
people have given me feedback on various aspects of the book. Based
on their feedback, I corrected some terminology inconsistencies and
typos. In particular, I thank David Clarke, Aaron Ebejer, Nicolas Gi-
aconia, Grant Mahoney, Ting, Chris Rowe, Mike Liang, and Max Lu
for their valuable inputs.
Daina Chiba
London, UK
January 10, 2016
(updated on September 14, 2020)
vii
Plan of the book
To improve your mahjong skills, you need not only to learn the
theories but also to practice what you learn by playing lots of games,
preferably with players who are stronger than yourself. Before the
advent of online mahjong platforms, however, doing so was not very
easy if you live outside of Japan.
Thanks to the recent development of online mahjong platforms, it
is now feasible for you to play hundreds or thousands of games with
serious opponents while living outside of Japan. On these websites,
you can easily find fellow players to play with 24/7. Most platforms
keep the record of all the games players have played and a replay
function that allows you to reflect on your past plays. You can also
take a look at player statistics, which gives you important clues as to
what skills you need to work on.
I thus recommend you practice mahjong skills by playing online
while you study the strategy principles with this book. You do not
need to wait until you finish reading everything covered in the book
before you start playing. Go ahead and play games first, then come
back to the book and study the relevant parts of the book.
This book is divided into four parts. Part I provides an intro-
duction to an online mahjong platform called Tenhou (天鳳). The
website is in Japanese, but I will walk you through the account regis-
tration process and show you how to play games in Chapter 1. There
already exist several excellent online resources that explain how to
play Tenhou, including:
• Arcturus’s Tenhou Documentation
Tenhou Documentation
viii PREFACE
• Complete Beginner’s Guide to Online Mahjong (Osamuko)
Complete Beginners Guide to Online Mahjong
• Playing Online: Tenhou (Reach Mahjong of New York)
Playing Online: Tenhou – Reach Mahjong of New York
If you have already read either of the three before, you can skip Chap-
ter 1 of this book, for there is not much new information there for you.
Chapter 2 explains some advanced features of Tenhou, which you can
also skip when you read this book for the first time.
Parts II and III are the “meat” of the book. Part II covers basic
tile efficiency theories that allow you to maximize the speed and/or
hand value of your hand. After introducing basic terminology in
Chapter 3, I discuss the five-block method in Chapter 4 and provide
some tips on how to pursue several yaku in Chapter 5. Part III covers
strategy principles, including score calculation methods (Chapter 6),
riichi judgement (Chapter 7), defense judgement (Chapter 8), meld-
ing judgement (Chapter 9), and so called “grand strategies” to win
a game (Chapter 10). Finally, Appendices include a chapter on eti-
quettes for offline playing (Chapter A) and another chapter on fur-
ther readings (Chapter B).
Numbers and letters shown in this color as well as each entry in
the Contents section below are hyperlinked; clicking on one will take
you to the pertinent page.
Contents
Preface iii
I Playing Riichi Online 1
1 Introduction to Tenhou (天鳳) 3
1.1 Why play online? . . . . . . . . . . . . . . . . . . . . . 3
1.2 Setting up an account . . . . . . . . . . . . . . . . . . . 4
1.3 The main page . . . . . . . . . . . . . . . . . . . . . . . 10
1.4 Playing a game . . . . . . . . . . . . . . . . . . . . . . 13
1.5 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . 26
1.6 Rules . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
2 Advanced features of Tenhou 30
2.1 Rank and rating . . . . . . . . . . . . . . . . . . . . . . 30
2.2 Four rooms . . . . . . . . . . . . . . . . . . . . . . . . . 35
2.3 Reading the statistics . . . . . . . . . . . . . . . . . . . 37
2.4 Viewing games . . . . . . . . . . . . . . . . . . . . . . 43
II Basic Tile Efficiency 46
3 Riichi mahjong basics 48
3.1 Learning strategies . . . . . . . . . . . . . . . . . . . . 48
3.2 Basic building blocks . . . . . . . . . . . . . . . . . . . 50
3.3 Complex shapes . . . . . . . . . . . . . . . . . . . . . . 65
3.4 Waits . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
ix
x CONTENTS
3.5 Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . 82
4 The five-block method 84
4.1 Finding a redundant tile . . . . . . . . . . . . . . . . . 85
4.2 Alternative configurations . . . . . . . . . . . . . . . . 88
4.3 Selecting tile blocks . . . . . . . . . . . . . . . . . . . . 97
4.4 Building a block . . . . . . . . . . . . . . . . . . . . . . 104
5 Pursuing yaku 110
5.1 How to get sanshoku . . . . . . . . . . . . . . . . . . . 111
5.2 How to get ittsu . . . . . . . . . . . . . . . . . . . . . 120
5.3 How to get pinfu . . . . . . . . . . . . . . . . . . . . . 125
5.4 How to get honitsu . . . . . . . . . . . . . . . . . . . . 128
5.5 How to get toitoi / chiitoitsu . . . . . . . . . . . . 134
III Strategy Principles 138
6 Scoring 140
6.1 Three steps in score calculation . . . . . . . . . . . . . 140
6.2 Basic scoring . . . . . . . . . . . . . . . . . . . . . . . . 142
6.3 Advanced scoring . . . . . . . . . . . . . . . . . . . . . 153
6.4 Scoring tables . . . . . . . . . . . . . . . . . . . . . . . 161
7 Riichi judgement 163
7.1 To riichi or not to riichi? . . . . . . . . . . . . . . . . . 163
7.2 Insta-riichi . . . . . . . . . . . . . . . . . . . . . . . . . 166
7.3 When not to riichi . . . . . . . . . . . . . . . . . . . . . 176
7.4 Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . 188
8 Defense judgement 189
8.1 To push or to fold? . . . . . . . . . . . . . . . . . . . . 189
CONTENTS xi
8.2 Defense basics . . . . . . . . . . . . . . . . . . . . . . . 193
8.3 Defense against riichi . . . . . . . . . . . . . . . . . . . 204
8.4 Defense against open hands . . . . . . . . . . . . . . . 208
8.5 Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . 215
9 Melding judgement 216
9.1 To meld or not to meld? . . . . . . . . . . . . . . . . . 216
9.2 Melding choice: examples . . . . . . . . . . . . . . . . 219
9.3 Calling kan . . . . . . . . . . . . . . . . . . . . . . . . . 225
9.4 Miscellaneous tips for melding . . . . . . . . . . . . . 231
10 Grand strategies 235
10.1 What to do in South-4 . . . . . . . . . . . . . . . . . . 235
10.2 What to do by South-3 . . . . . . . . . . . . . . . . . . 244
10.3 Tables for induced point differences . . . . . . . . . . 247
Appendices
A Manners for offline playing 250
A.1 Dealing tiles . . . . . . . . . . . . . . . . . . . . . . . . 250
A.2 Drawing and discarding . . . . . . . . . . . . . . . . . 252
A.3 Calling . . . . . . . . . . . . . . . . . . . . . . . . . . . 254
A.4 Winning a hand . . . . . . . . . . . . . . . . . . . . . . 255
B Further readings 260
B.1 Books on riichi mahjong . . . . . . . . . . . . . . . . . 260
B.2 Online resources . . . . . . . . . . . . . . . . . . . . . . 262
Part I
Playing Riichi Online
1

Chapter 1
Introduction to Tenhou (天鳳)
1.1 Why play online?
Playing mahjong online is an excellent way to practice your mahjong
skills. You don’t need any mahjong equipment to play; you don’t
need to coordinate with your mahjong friends to find the time and
place that work for all four of you. You can simply open your com-
puter and access one of many online mahjong platforms. As long
as you have an internet connection, you can play mahjong any time,
anywhere, and for any length of time.
Another advantage of online playing is that you can easily keep
the record of your playing history and obtain detailed statistics from
all the games you play. Analyzing these statistics will help you iden-
tify what skill sets you need to work on. You can also show your
game record to your friends and ask for their opinions about partic-
ular choices you’ve made in a game.
天鳳 (Tenhou) is arguably the
most popular online mahjong plat-
form in the world. As of December,
2015, there are over three hundred
thousand active players on Tenhou.1
A lot of professional mahjong play-
ers from Japan now play Tenhou.
There are also some Tenhou players who have later become profes-
sional after practicing their skills on Tenhou. It has become a common
1 To be exact, it has 304,534 active players and 3,566,353 registered players as of
20 December, 2015.
4 CHAPTER 1. INTRODUCTION TO TENHOU (天鳳)
understanding among players in Japan that your rank and rating on
Tenhou are one of the most reliable indicators of your mahjong skill
levels. To get you started, this chapter explains how to set up an ac-
count on Tenhou and provides a basic operation manual.
1.2 Setting up an account
One of the challenges for European players in setting up an ac-
count on Tenhou would be that almost everything is written in Japanese.
However, you will only need a minimal level of Japanese to get by,
and this chapter will walk you through the process.
First, go to the Tenhou webpage (http://tenhou.net/).
Scroll down and click either the PLAY button (to play in a pop-up
window) or a link just below the button (to play in the current win-
dow) that reads このウィンドウで開く.
Click here to play
in a pop-up
window.
Click this link to
play in the
current window.
1.2. SETTING UP AN ACCOUNT 5
Then, on the next page (either in a pop-up window or in the cur-
rent window), you’ll see something like the following:
Flash version Web version
The bottom line will initially read LOADING… / 再読み込み, but
in a few seconds it will change into »Flash 版サーバに接続 | Web 版
β サーバに接続. Then, click on the Flash サーバに接続 link if you are
accessing from a flash-capable device such as your PC; alternatively,
click on the Web 版 β サーバに接続 link if you are accessing from a
smart phone or tablet. If it doesn’t change into »Flash 版サーバに接
続 | Web 版 β サーバに接続 within 10 seconds or so, you may want
to click on the 再読み込み link right next to LOADING, which will
prompt the browser to reload the page. Clicking on either of the
Flash/Web サーバに接続 links will take you to the log-in entrance of
Tenhou. Explanations below are based on the Flash version.
6 CHAPTER 1. INTRODUCTION TO TENHOU (天鳳)
Registration ID field (likely to be blank at first)
When you first visit this page, the ID field right next to the 新規
ID 登録 button is likely to be blank, as shown in the picture above.
This is because you haven’t registered an account. In order to create
an account, click on the 新規 ID 登録 (New ID Registration) button
on the left.
A pop-up message will show up, warning you that whatever ID
that is currently shown in the ID field (if any) will be overwritten
with a new ID and that you may want to copy and paste the current
ID (if any) into some text file or similar. Do so if you do see an old
ID in the ID field, just to be safe. If the ID field is blank, just click the
Yes button, which will open yet another pop-up message.
1.2. SETTING UP AN ACCOUNT 7
It is telling you the following:
• You can create a player ID for free, and doing so is necessary if
you want to earn a rank (kyuu / dan) and rating.
• Some characters or character combinations are not allowed in
player names.
• Once you register, you cannot register another account for a
given period (7 days).
• If you don’t play for 180 days, your ID may be deleted.
• A player name must have 1-8 characters.
Type in a player name you’d like to have (8 characters or fewer)
into the blank field at the bottom and click OK. You cannot change
your player name later, so choose wisely. If the player name you type
in is already taken by another player, it gives you an error message,
as follows:
This player name is taken.
Click OK, and type in another name. If successful, you’ll see a
new message asking you to confirm that you want to register an ac-
count with the player name provided.
8 CHAPTER 1. INTRODUCTION TO TENHOU (天鳳)
Click Yes and you’ll see another message as follows:
The 19-digit alpha-numeric code that starts with “ID” (shown in
white on a black background) is your unique player ID (it is ID12345678-
ABCDEFGH in the picture above). I suggest you save your ID in a
text file or something so that you don’t lose it. They cannot re-issue
your player ID (unless you have a paid membership and hold a rank
of 七段 or higher).
Clicking OK will take you back to the log-in entrance page, but
this time you should see your player ID in the ID field.
1.2. SETTING UP AN ACCOUNT 9
Your player ID Choose 男 (male voice) or 女 (female voice)
Can choose
プレミアム or
エコノミー.
You can make several choices before entering the main page. First,
you can choose male or female voice (for pon / chii / riichi, etc.) by
clicking on the button right next to the ID field. You can choose a
different gender each time you log in to the main lobby. Second, you
can choose プレミアム (premium) or エコノミー (economy) version.
The premium version has better graphics, so I suggest you choose
the premium version.
If you are happy with your choices, you can enter the main page
by clicking on the OK button on the right.
10 CHAPTER 1. INTRODUCTION TO TENHOU (天鳳)
1.3 The main page
Here is what the Tenhou main page looks like when you first log
on in. The right half of the main page shows your statistics (currently
all the fields are blank because you haven’t played any games), and
the left half shows the games you can play and some other features.
Menu Cancel (to cancel a reservation)
Main tabs
Sub tabs
In the second line of the left hand side, you see three numbers. In
the example above, they are 1857, 915, and 118 (the numbers will be
different on your screen). These numbers show that 1857 players are
currently online, 915 players are waiting, and 118 players are about
to finish their games.
Below these three numbers, there are six main tabs, which read 段
位戦, 雀荘 β, 技能 β, 観戦, 牌譜, and ヘルプ. The 段位戦 tab is the main
lobby where we play games (段位戦 reads dan-i-sen in Japanese; it
means ranking matches). Under the 段位戦 tab, there are four sub
tabs, which read 一般, 上級, 特上, and 鳳凰, corresponding to four
1.3. THE MAIN PAGE 11
different rooms. At first you can only play at tables in the 一般 room.
Let’s first go to the 段位戦 tab, and choose the 一般 sub tab.
Making reservations
In each of the four rooms (i.e., 一般, 上級, 特上, and 鳳凰), there
are 12 different variants of riichi mahjong games you can choose from.
Games in the left column (under 東風戦 tonpusen) are East-only
games,2 and games in the right column (under 東南戦 tonnansen)
are more standard East-South games that have both East and South
rounds.3
Closed tanyao
Open tanyao
With red fives
Fast
Three-player
Fast (3p)
East-only East–South
1 player waiting
44 players playing
Games in the first row (喰断ナシ kuitan nashi) are unusual games
where open tanyao (All Simples) is not allowed; you have to have
a concealed hand to claim tanyao.4 There are no red fives in these
games, either. Open tanyao is allowed in all the other games. Games
2 In a special circumstance where no player gets 30000 or more points by the end
of East-4, the game continues into the South round.
3 Just like East-only games, when there is no player who has 30000 or more points
by the end of South-4, the game continues into the West round.
4 kuitan means “open tanyao” and kuitan nashi means “without kuitan” in
Japanese.
12 CHAPTER 1. INTRODUCTION TO TENHOU (天鳳)
in the second row are more standard games with open tanyao, but
they do not have red fives. Games in the third row have three red
fives. This is arguably the most standard type of riichi mahjong game
played in Japan as of now. Games in the fourth row have the same
rule as those in the third, but the time limit on each action is more
strict. Games in the fifth and sixth rows are three-player games,
where open tanyao and red fives are both allowed.
The set of numbers delimited by a colon in each cell represent
the numbers of players currently waiting and playing the game, re-
spectively. For example, the first row in the left column shows 3:24,
which means that 3 players are waiting in queue after signing up for
a game, and 24 players are currently playing East-only, closed tanyao
games. As it happens, East-South games with red fives are usually
the most popular on Tenhou, followed by East-only, fast games.
To sign up for a game, click on the 予約 (reservation) button in
the corresponding cell. You can make as many reservations as you
want; you will be given a seat at a table that first becomes available. If
you make multiple reservations, other reservations will be automat-
ically canceled when you start playing at another table. To cancel all
the reservations at once, click on the キャンセル (Cancel) button at
the bottom right of the left-hand side of the main page. The cancel
button becomes active (clickable) only after you make a reservation.
1.4. PLAYING A GAME 13
1.4 Playing a game
Once a slot becomes available for
you, you will be taken to a game ta-
ble along with three other players. A
black pop-up screen (see right) will
appear. The game will start in 10 sec-
onds (if all the four players click on
the OK button, the game will start
immediately). Each player is ran-
domly assigned to East, West, South, or North. In the example above,
my initial seat wind is North (北).
The Tenhou interface is quite intuitive so you won’t need much
instruction. Once a hand begins, tiles are dealt automatically. You
also automatically draw a tile when your turn comes. In each turn,
click on the tile you want to discard.
Each action is timed. At a standard (non fast) table, you have 5
seconds to discard a tile. In addition, you are given a total allowance
of 10 seconds in each hand. That is, even when you use up the 5 sec-
14 CHAPTER 1. INTRODUCTION TO TENHOU (天鳳)
onds allocated to you in a particular turn, you will be given the max-
imum 10 additional seconds (minus the seconds you have already
used up in previous turns in the hand). For example, when you use
5 + 4 seconds in the first turn, the remaining allowance reduces to
10 4 = 6 seconds in this hand. Therefore, the next time you use
up the first 5 seconds, you will be given only 6 more seconds. The
allowance will increase by 1 second (up to 10 seconds) each time you
make your discard choice in less than 1 second. The allowance will
revert to 10 seconds when the next hand begins. At fast tables, each
action must be done in 3 seconds, with a total allowance of 5 seconds.
1.4.1 Calling / melding
When a call becomes available, a box with a call name will show
up to prompt your reaction. The call prompts are written in Japanese.
The good news is that they are relatively simple and easy to guess
from the context. It would be enough to memorize the following
eight mahjong words in Japanese.

  1. リーチ riichi [r´I:tS]
    You can call riichi when you have (1) a closed ready hand, (2) at
    least 1000 points left, and (3) at least one turn left to draw. When all
    of the three conditions are met, a translucent box that reads リーチ
    in white letters will pop up in your turn.
    If you want to riichi, you must click on the リーチ box first, then click
    on the tile you want to discard. Once you click on the リーチ box, you
    cannot call it off. Clicking on the リーチ box also makes it impossible
    to discard a tile that does not make the hand ready. In the above ex-
    1.4. PLAYING A GAME 15
    ample, tiles other than ȷ will become unclickable once you
    click on the リーチ box. If you do not want to call riichi, just click on
    the tile you want to discard.
  2. ロン ron [r´ON]
    A ロン box will pop up whenever you can legitimately declare
    ron on an opponent’s discard. In other words, chombo is made im-
    possible on Tenhou. For example, when you are furiten, a ロン box
    will not pop up because you cannot legally ron with a furiten hand.
    Whenever your hand is in a furiten status, it is indicated with a フ
    リテン (furiten) sign in small translucent letters below your hand
    that looks like: . If you don’t click on the ロン box in time
    (i.e., in 5 or 3 seconds + allowance), it is assumed that you pass.
  3. パス Pass (do nothing)
    Whenever a ロン box pops up, another box that reads パス (pass)
    will accompany it.
    Click on the パス box immediately if you don’t want to declare ron
    on a discard. You would not want to pause for too long because that
    can look suspicious. A パス box will also pop up when other calling
    actions become available.
  4. ツモ tsumo [ts´umo]
    A ツモ box will pop up when you can legitimately declare tsumo
    with your draw.
    16 CHAPTER 1. INTRODUCTION TO TENHOU (天鳳)
  5. ポン pon [p´ON]
    When calling pon becomes available, a ポン box will pop up right
    above the tiles in your hand with which to call pon. A パス box will
    also pop up. If you want to call pon, mouse over the tiles in your
    hand with which to call pon. Then the candidate tiles will stick out,
    as follows:
    Click on them to call pon. If you click on the パス box or don’t do
    anything in time, it is assumed that you pass.
  6. チー chii [tS´I:]
    Chii calls are done in a similar way. When it becomes available,
    a small sign that reads チー will pop up right above the tiles in your
    hand with which to call chii.
    When you have multiple sets of tiles with which to chii, as is the
    case in the above picture, mouse over the candidate tiles to choose.
    In the picture above, the left player discarded a and you can chii
    it with either , , or . If you want to chii it with ,
    mouse over the then the and the will stick out so you can
    click on them. If you want to chii it with , mouse over the
    then the and a will stick out so you can click on them. Finally,
    if you want to chii it with , mouse over the left then the
    and the will stick out so you can click on them.
    1.4. PLAYING A GAME 17
  7. カン kan [k´2N]
    Calling kan on a discard is similar to calling pon. Calling kan by
    extending a melded pon may be a little bit confusing at first. When
    you have a melded pon and there is the fourth tile in your hand
    (newly drawn or previously drawn), a small sign that reads カン
    will appear below the pon upon your turn. If you want to extend
    the melded pon, mouse over the melded pon then the fourth tile will
    stick out. Click on the melded pon to extend the pon. To call a con-
    cealed kan, mouse over the four tiles you want to kan then the tiles
    will stick out, accompanied by a small sign that reads カン below
    them. Click on them to call kan.
  8. 九種九牌 Kyuushu Kyuuhai
    When you have nine different terminals and honors after the first
    draw in an uninterrupted first set of turns, you can declare an abortive
    draw. When this becomes available, a box that reads 九種九牌 will
    pop up. Click on it if you want to declare an abortive draw. If you
    wish to continue with the hand, just click on the tile you want to dis-
    card.
    Multiple boxes
    Sometimes you have multiple choices as to what to do with a
    given discard of your opponent. In the following example, you have
    a ready hand waiting for -, and the left player discarded a .
    You will be given the following three choices:
    Ron Pass
    Chii
    18 CHAPTER 1. INTRODUCTION TO TENHOU (天鳳)
    • Call ron
    • Call chii
    • Pass (do nothing)
    To call ron on the discarded , click on the ロン (ron) box that pops
    up above your hand. If you want to do nothing, click on the パス
    (pass) box right next to the ロン box. Alternatively, if you want to
    call chii, mouse over the two tiles you want to chii with (in this
    case ) and click on them.
    1.4.2 Buttons
    The buttons at the bottom right corner allow you to toggle on/off
    some calling-related features. Each feature is turned off at the begin-
    ning of a new hand.
    Auto call win
    Auto discard draw
    No call Picture (画)
    Sound (音)
    自動和了 (Auto call win)
    If you turn this on, you will automatically win a hand when possi-
    ble without clicking on ロン or ツモ boxes. In other words, the option
    of passing is unavailable when this is turned on. Keep in mind that
    this can be problematic at times when you intend not to win your
    hand from a particular opponent or on a particular tile. When this
    is turned on, the word 自動和了 is shown in white; when it is turned
    off, it is translucent. In the picture above, it is turned on.
    ツモ切り (Auto discard draw)
    If you turn this on, you will automatically discard whatever tile
    you draw. Turn this on when you have to go to toilet or somewhere
    1.4. PLAYING A GAME 19
    but don’t want to quit the game entirely. When you riichi, this feature
    is automatically (and implicitly) turned on. In the picture above, it
    is turned off.
    鳴かない (No call)
    If you turn this on, you will not be prompted to call chii, pon, or
    kan. This feature is useful for hiding information about your hand’s
    tile composition from your opponents. If you pause every time some-
    one discards a certain tile you can call, your opponents might be able
    to guess what pairs of tiles you have and don’t have. Drawing a de-
    duction from such time lags constitutes an important skill in Tenhou.
    However, in order not to disadvantage players waiting to call chii /
    pon too much, time lags will also occur randomly (i.e., even when no
    one can call pon / chii on the discarded tile).
    画 (Picture) and 音 (Sound effect)
    You can change the appearance of the tiles and/or mat or resize
    the window with the Picture button. You can turn on/off the sound
    effect (for riichi, chii, pon, etc.) with the Sound button.
    20 CHAPTER 1. INTRODUCTION TO TENHOU (天鳳)
    1.4.3 Scoring
    When a player wins a hand, the score will be calculated auto-
    matically. A scoring board will pop up that shows the hand, dora
    (and ura dora if riichi was declared), yaku names and the associ-
    ated number of han, minipoints, and the total hand value.
    In the example above, the left player dealt into my hand that is worth
    60 符 (fu; minipoints) 13 飜 (han) = 32000 点 (points). Yaku names
    will be shown in Japanese along with han counts. Table 1.2 at the end
    of this chapter lists all the yaku names Tenhou recognizes.
    1.4. PLAYING A GAME 21
    1.4.4 Indicators
    The black rectangular board in the middle of the screen provides
    information about the proceeding of the game.
    Number of
    riichi bets
    Counter
    We can see that this is South-4, there is 0 counter and 0 riichi bet,
    and it is the North player’s turn. The West player is leading (44000
    points), followed by the East player (26800), the North player (17400),
    and the South player (11800). Each player’s rank (kyuu / dan) is
    shown right next to their points.
    If you mouse over the middle board, you will see the current
    point differences between you and each of your opponents. In the
    present example, the West player has 44000 26800 = +17200 more
    points than I do. If you are leading against another player, the point
    difference will be negative. For example, the South player has 11800
    so the point difference is 11800 26800 = 15000.
    22 CHAPTER 1. INTRODUCTION TO TENHOU (天鳳)
    It is important to pay close attention to these point differences, es-
    pecially in the South round or when one of your opponents is at the
    risk of bankruptcy. In the current example, if the East player wins a
    12000 hand from the South player, South will go bankrupt and the
    game is terminated. Notice that East is currently ranked second, hav-
    ing 17200 points fewer than West. In this case, winning a 12000 from
    South is not ideal for East because East will still be ranked second
    and the game is over.5
    You can also see the type of game you are currently playing on
    the board. Just below the wall opposite to you is an indicator that
    looks like this: .
    • The first letter indicates the room: 般 for 一般 (ippan), 上 for 上
    級 (joukyuu), 特 for 特上 (tokujou), 鳳 for 鳳凰 (houou). See
    Chapter 2 for explanations of these.
    • The second letter indicates if it is an East-only game (東) or an
    East–South (南) game.
    • The third letter indicates if open tanyao is allowed: 喰 (with
    open tanyao) or 無 (without open tanyao)
    • A fourth letter (赤) is added if there are red fives.
    • A fifth letter (速) is added if it is a fast game.
    5 As we will see later, avoiding the fourth place is more important in Tenhou rules
    than it is in other rules. However, this does not mean that it is your only priority;
    you would still want to improve your placement in a game when doing so is a
    realistic possibility.
    1.4. PLAYING A GAME 23
    1.4.5 Ending of a game
    A game can end in several different ways.
    • One or more player goes bankrupt (below 0 points).
    • South-4 (East-4 in East-only games) ends and at least one player
    has 30000 or more points.
    • West-4 (South-4 in East-only games) ends.
    • At any point in the West round (South round in East-only games),
    at least one player has 30000 or more points.
    When a game ends, final scores are calculated as follows.
    • In cases of a tie, the player sitting closer to the first dealer wins.
    • Oka (winning premium) is 20000. That is, although every player
    is allocated 25000 points at the beginning of a game, they have
    to return 30000 at the end of the game, meaning that 30000 will
    be subtracted from the final raw scores. The residual points of
    20000 = (30000 25000) 4 are awarded to the winner of the
    game.
    • Uma (placement bonus) is 10-20. That is, 1st player gets +20000,
    2nd player gets +10000, 3rd player gets 10000, and 4th player
    gets 20000.
    • Each score is then scaled by dividing it by 1000 and rounding it
    off.
    It appears that European players are not very familiar with the
    oka system (possibly because there is no oka in EMA rules), so let
    me explain this with an example. Suppose that players A, B, C, and
    24 CHAPTER 1. INTRODUCTION TO TENHOU (天鳳)
    Table 1.1: Final score calculation on Tenhou
    Player Raw score Before uma After uma After oka
    A 39000 9000 29000 49000
    B 25100 4900 5100 5100
    C 22900 7100 17100 17100
    D 13000 17000 37000 37000
    D hold the following raw points at the end of a game; 39000, 25100,
    22900, and 13000, as shown in Table 1.1 below.
    The first numerical column shows the raw scores. Then, 30000 is
    subtracted from each of the raw scores (second column). Then, we
    add uma to each score based on placements (third column). Finally,
    we add oka to the winner’s score to obtain the final scores (fourth
    column).
    The final scores after adding
    uma and oka and scaling will be
    displayed along with the place-
    ments and raw scores. In the ex-
    ample to the right of this text,
    I (私 means “me”) came in 1st,
    earning 50100 points (60.0 with
    uma and oka), 2nd player (C さん,
    which reads Mr. C) earns 46000
    points (+ 26.0 with uma), 3rd
    player earns 6700 points (33.0
    with uma), and 4th player went bankrupt (2800 points, 53.0 with
    uma).
    1.4. PLAYING A GAME 25
    bababababababababababababababab
    Notes on placement
    It is important to keep in mind that your rank and rating on Tenhou
    depend solely on the placement in a game and not on how many
    points you earn in a game, before or after adding uma and oka.
    In other words, there is absolutely no difference between getting
    1st place with 30000 points and getting 1st place with, say, 80000
    points in terms of their contributions to your rank and rating.a
    This feature adds an interesting strategic element to the game.
    That is, it makes it clearer that the goal of mahjong is not to win
    a hand per se but to have a better placement at the end of a game.
    Winning a hand is just one of several means to securing a good
    placement. On occasion, you may find it beneficial to assist one
    of your opponents instead of trying to win a hand yourself. Inten-
    tionally dealing into an opponent’s hand can sometimes be a good
    tactic when it serves the purpose of securing your own placement.
    In my impression, many European players are lacking the appreci-
    ation of this aspect of mahjong. I hope you will learn to appreciate
    it through playing lots of games on Tenhou.
    a You might wonder why they still calculate the final scores with uma
    and oka in Tenhou if they are irrelevant; I honestly have no idea.
    26 CHAPTER 1. INTRODUCTION TO TENHOU (天鳳)
    1.5 Troubleshooting
    At times, you may get disconnected from the Tenhou server (pos-
    sibly because of poor internet connection on your end or problems
    on the server).6 When a player gets disconnected from the server
    during a game, the game still continues. The “auto discard draw”
    will be turned on for the disconnected player, so they will be simply
    discarding anything they draw until they return. The player name
    will turn into dark red once a player is disconnected.
    When you get disconnected,
    you may get a warning mes-
    sage shown above, asking you
    if you would like to get con-
    nected again. Click Yes if you
    want to. However, a warning
    message does not always show up when you get disconnected. When
    a screen freezes during a game for more than 15 seconds, you should
    suspect that you are disconnected. You may want to hit the refresh
    button on your browser to get connected to the server again.
    You can create more than one accounts on Tenhou, but you will
    have to wait for 7 days unless your IP address changes. If you at-
    tempt to create a second account from the same IP address within
    7 days, you will get an error message shown below, telling you that
    you cannot create a new account from your IP address in 7 days.
    6 You will notice that players sometimes get disconnected on purpose to quit
    playing, especially when they are losing badly.
    1.6. RULES 27
    1.6 Rules
    Here is a summary of the rules on Tenhou.
    • Three red fives (one in each suit) in games with red fives.
    • No kuikae (swap-calling). That is, you cannot discard an iden-
    tical tile after pon or chii. You cannot discard the tile from other
    end of the run, either.
    • “Sudden death” rule when no player has 30000 or more points
    after South-4 (East-4 in East-only games).
    • A game is terminated when a player goes bankrupt.
    • Automatic agariyame rule (i.e., the game is automatically ter-
    minated if the dealer is leading after the end of South-4, even if
    he won a hand in South-4).
    • One-han minimum all the time (i.e., no two-han minimum even
    after five counters).
    • Abortive draw in the following situations:
    – 九種九牌 (nine terminals / honors)
    – 四家立直 (four riichi’s)
    – 三家和了 (three players call ron on a discard)
    – 四風子連打 (four players discard the same wind)
    – 四槓散了 (four kan by different players)
    • 流し満貫 (nagashi mangan) is allowed. You can declare it even
    when you have called pon / chii. You cannot declare it if one
    or more of your discards has been called by others.
    28 CHAPTER 1. INTRODUCTION TO TENHOU (天鳳)
    • Up to two players can win on a discard. riichi bets and counter
    bonus go to the player sitting closer to the player who discarded
    the winning tile. The dealership remains if the dealer is one of
    the winners.
    • The following are recognized as yakuman: 天和 (Tenhou; Bless-
    ing of Heaven) / 地和 (chihou; Blessing of Earth) / 大三元 (daisangen;
    Big Three Dragons) / 四暗刻 (su anko; Four Concealed Pungs)
    / 四暗刻単騎 (su anko tanki; Single-Wait Four Concealed Pungs)
    / 字一色 (tsuiisou; All Honors) / 緑一色 (ryuiisou; All Green)
    / 清老頭 (chinroutou; All Terminals) / 国士無双 (kokushi muso;
    Thirteen Orphans) / 国士無双 13 面 (Thirteen-wait Thirteen Or-
    phans) / 大四喜 (daisushi; Big Four Winds) / 小四喜 (shosushi;
    Little Four Winds) / 四槓子 (su kantsu; Four Kongs) / 九蓮宝燈
    (churenpoutou; Nine Gates) / 純正九蓮宝燈 (junsei churenpoutou;
    Nine-wait Nine Gates).
    • Yakuman can be combined. For example, 大三元 (Big Three Drag-
    ons) can be combined with 字一色 (All Honors), 四暗刻 (Four
    Concealed Pungs), and either of 四槓子 (Four Kongs), 天和 (Bless-
    ing of Heaven) or 地和 (Blessing of Earth), producing a quadru-
    ple yakuman (128000 points).
    • There is no double yakuman unless different yakuman are com-
    bined. For example, 国士無双 (Thirteen Orphans) and 国士無双
    13 面 (Thirteen-wait Thirteen Orphans) are both single yakuman.
    • You cannot call pon / chii / kan on the last discard in a hand.
    • Sekinin barai: a player who feeds the third Dragon pon / kan
    to an opponent with two melded Dragon pon / kan must pay
    the full value of the hand in case Big Three Dragons is made on
    a self-draw. In case another player deals into it, the two share
    1.6. RULES 29
    the payment equally. The same rule applies to Big Four Winds,
    but not to rinshan kaihou (After a Kong).
    Table 1.2: List of yaku names
    Yaku Pronunciation EMA name Han (open)
    門前清自摸和 (menzen-) tsumo Fully Concealed Hand 1 (NA)
    立直 riichi Riichi 1 (NA)
    一発 ippatsu Ippatsu 1 (NA)
    槍槓 chankan Robbing the Kong 1
    嶺上開花 rinshan kaiho After a Kong 1
    海底摸月 haitei (-moyue) Under the Sea 1
    河底撈魚 houtei (-raoyui) Under the River 1
    自風 jikaze Seat Wind 1
    場風 bakaze Prevailing Wind 1
    役牌 yakuhai / fanpai Dragon Pung 1
    断幺九 tanyao All Simples 1
    一盃口 iipeiko Pure Double Chow 1 (NA)
    平和 pinfu Pinfu 1 (NA)
    混全帯幺九 chanta Outside Hand 2 (1)
    一気通貫 ittsu Pure Straight 2 (1)
    三色同順 sanshoku (-doujun) Mixed Triple Chow 2 (1)
    三色同刻 sanshoku doukou Mixed Triple Pungs 2
    両立直 double riichi Double Riichi 2 (NA)
    三槓子 san kantsu Three Kongs 2
    対々和 toitoi All Pungs 2
    三暗刻 san anko Three Concealed Pungs 2
    小三元 shousangen Little Three Dragons 2
    混老頭 honroutou All Terminals and Honors 2
    七対子 chiitoitsu Seven Pairs 2 (NA)
    純全帯幺九 junchan Terminals in All Sets 3 (2)
    混一色 honitsu Half Flush 3 (2)
    二盃口 ryanpeiko Twice Pure Double
    Chow
    3 (NA)
    清一色 chinitsu Full Flush 6 (5)
    流し満貫 nagashi mangan – mangan
    ドラ dora Dora
    赤ドラ aka dora Red five
    裏ドラ ura dora Ura dora
    Chapter 2
    Advanced features of Tenhou
    2.1 Rank and rating
    Tenhou has two different player Rank N Rank N
    天鳳位 9
    十段 15 1級 7780
    九段 130 2級 5849
    八段 592 3級 6481
    七段 1830 4級 6383
    六段 3140 5級 6971
    五段 5968 6級 9964
    四段 9957 7級 16606
    三段 14436 8級 14509
    二段 18174 9級 28283
    初段 15046 新人 132411
    Table 2.1: Player distribution
    rating systems — rank (kyu / dan)
    and R (rate). The kyu / dan rank-
    ing system is similar to the one com-
    monly used in Japanese arts, games,
    and martial arts. The kyu (級) ranks
    are shown in arabic numbers, go-
    ing from 9 級 to 1 級 in descending
    order. After passing 1 級, you enter
    the dan (段) ranks, shown in kanji
    numbers, going from 初段 (一段;
    first dan) to 十段 (tenth dan) in as-
    cending order. Everyone starts with
    新人 (newbie; no rank), and if you pass the 十段 rank, you are awarded
    the highest rank called 天鳳位 (Tenhoui). Since the inception of Tenhou
    in 2006, there have been only nine players who have achieved 天鳳位
    at the time of writing this book. Table 2.1 shows the distribution of
    active players holding each rank as of 20 December, 2015.
    2.1.1 kyu / dan rank
    To advance your kyu / dan rank, you need to earn points (called
    “pt” or “段位 pt” on Tenhou). For example, to proceed from the 新
    人 (newbie) status to the 9 級 (kyu) rank, you need to earn 30 points.
    Required amount of points for promotion gets greater and greater as
    you move further up. For example, to proceed from 六段 (sixth dan)
    2.1. RANK AND RATING 31
    to 七段 (seventh dan), you need to earn as many as 1200 points.
    To find out how many more points you need to earn to advance
    to the next rank from the current rank, see the top right part of the
    main page.
    Your current
    rank (7 級)
    pt you have /
    pt you need
    Your R
    In this example, the player currently holds the rank of 7 級. The part
    that reads “30 / 60 pt” means that he has earned 30 points since he
    became 7 級 and that he needs 60 points in total to be promoted to
    6 級.
    When you rise or fall in rank, your points will be reset to a default
    value. For kyu rank players, the default value is 0 points. For dan
    rank players, the default value is different depending on ranks. For
    example, the default points for 六段 players are 1200 points. When
    they get 1200 more points and reach 2400 points, they get promoted
    to 七段. When they lose all the initial 1200 points and reach 0 points,
    they get demoted to 五段.
    The amount of points you earn or lose in each game depends on
    your placement (but not scores with uma and oka), the type of game
    (East-only or East–South), the room in which the game is played (一
    般, 上級, 特上, or 鳳凰), and your current rank.1 You gain positive
    points only if you come in first or second place. If you come in first
    place, you will gain the following points regardless of your rank.
    1 Points you earn or lose in East-only games are two-thirds of those in East–South
    games.
    32 CHAPTER 2. ADVANCED FEATURES OF TENHOU
    • 45 points in the 一般 (ippan) room
    • 60 points in the 上級 (joukyu) room
    • 75 points in the 特上 (tokujou) room
    • 90 points in the 鳳凰 (houou) room
    If you come in second place, you will gain the following points re-
    gardless of your rank.
    • 0 points in the 一般 room
    • 15 points in the 上級 room
    • 30 points in the 特上 room
    • 45 points in the 鳳凰 room
    You don’t gain or lose points if you come in third place. The points
    you lose when coming in fourth place depend on your rank but not
    on the room. When your rank is 3 級 or below, you lose 0 point. How-
    ever, each time your rank rises above 3 級, the points you lose get big-
    ger by 15 points. That is, 2 級 players lose 15 points if they come in
    fourth place; 1 級 players lose 15 2 = 30 points; 初段 players lose
    15 3 = 45 points, … , and 十段 players lose as many as 180 points if
    they come in fourth place.
    Notice how severe the punishment is for coming in fourth, and
    it gets more and more severe as your rank goes up. This is one of
    the distinctive features of Tenhou. Avoiding the fourth place tends to
    be players’ top priority in Tenhou games. This is in contrast to stan-
    dard mahjong games, where the reward for coming in first usually
    outweighs the cost of coming in fourth, thanks to the oka system.2
    2 Recall that, although Tenhou does adopt the oka system, it is the placement,
    not the scores, that determines the points you earn or lose. In this sense, EMA
    games are actually more similar to Tenhou games than to standard games. Since
    there is no oka in EMA games, the reward for coming in first is much smaller
    than that in standard games.
    2.1. RANK AND RATING 33
    To easily find out how many
    points you earn / lose for each place
    in a given type of game for your rank,
    mouseover the 予約 button in each
    cell on the left-hand side of the main
    page. Then, you will see something
    like the picture above on the right-hand side of the main page. Under
    the second bullet point, we see that, for this player’s rank (五段), the
    point reward is: +75 for first place, +30 for second place, 0 points for
    third place, and 105 for fourth place.
    When you earn enough
    points for promotion in a game,
    a new rank is awarded after
    the game. A certificate mes-
    sage like the picture to the
    right of this text will pop up af-
    ter the game.
    Since you never get negative points in games until you reach 2 級
    and there is no demotion until you reach 初段 (first dan), it should
    be relatively easy to reach 初段. In fact, even without studying the
    contents of this book, you can perhaps reach as high as 四段 (fourth
    dan) if you play a few hundred games or so. However, moving fur-
    ther up will probably require that you study basic strategies and tile
    efficiency theories.
    2.1.2 Rate (R)
    In addition to the kyu / dan rank, Tenhou gives each player an-
    other rating called R. The initial value of R is 1500, and higher-rank
    players tend to have a higher R. For example, the average R among
    34 CHAPTER 2. ADVANCED FEATURES OF TENHOU
    the 天鳳位 players is 2248.
    While kyu / dan rank remains relatively stable, R can change af-
    ter each game. R is calculated based on your placement in a game,
    but it also depends on the average R of the players you play with. A
    change in R after a game, ∆R, is calculated with the following for-
    mula:
    ∆R = (P + R) G
    where
    • P is based on your placement in the game: + 30 for first, +10
    for second, 10 for third, and 30 for fourth;
    • R is an adjustment that reflects how strong your opponents are,
    calculated as (Average R in the game your R) / 40; and
    • G is an adjustment based on n, the number of games you have
    played before. If n 400, G is equal to 1 0.002 n. If n > 400,
    G is set equal to 0.2.
    R initially fluctuates a lot, as the scaling factor G is very close to
    1 until you play many games. R may go up or down by 30 or so for
    each of the first 100 games or so. As you play more games, however,
    the fluctuation gets smaller and smaller as G approaches to 0.2.
    Notice what the adjustment R does. This factor is positive when
    you play against players who are “stronger” than you (i.e., have a
    higher R than you) while it is negative when you play against play-
    ers who are “weaker” than you. Therefore, when you win against
    stronger players, your reward will be bigger than when winning against
    weaker players. Likewise, when you lose against weaker players,
    your punishment will be severer than when losing against stronger
    2.2. FOUR ROOMS 35
    players. Because of these features, one might say that your R better
    reflects your skill levels than your kyu / dan rank.
    2.2 Four rooms
    As we have seen, there are four different rooms where ranking
    matches are played. Qualifications to play in each room are based
    on your rank and R.
  9. 一般 (ippan; lower-level room)
    This is the only room where you can play initially. Players with
    an R higher than 1800 and a rank higher than 四段 are not allowed to
    play here, however. Games in this room can sometimes be a bit ran-
    dom, even chaotic at times. Some of the players in this room probably
    do not understand the rules very well. You very rarely come across
    strong players here.
  10. 上級 (joukyu; upper-level room)
    You can play here if (1) your rank is 1 級 or higher or (2) you buy
    a two-month membership (¥ 1080 = e 8 = £ 6).3 Players with an R
    higher than 2000 and a rank higher than 七段 are not allowed to play
    in this room, however.
    Games in the joukyu room are more reasonable than those in the
    lower-level room, but you still see many players who do not defend
    at all, do meaningless dama / unreasonable riichi, and make serious
    mistakes in maximizing tile efficiency. In my impression, games at
    EMA tournaments most resemble games in the ippan and joukyu
    rooms.
    3 If you want to pay for the membership, click on the link that appears when you
    click the 上級 sub-tab. Keep in mind that you need to buy 60 days’ worth of
    membership. Choose “60 日分を購入 (1080 円)” in the payment page.
    36 CHAPTER 2. ADVANCED FEATURES OF TENHOU
  11. 特上 (tokujou; advanced room)
    Requirements to play in this room are pretty demanding. You
    have to have a 四段 or higher rank and a 1800 or higher R. The latter
    requirement is particularly difficult to satisfy for intermediate play-
    ers. As I wrote above, achieving the rank of 四段 is not that difficult,
    but satisfying the R 1800 condition requires that you take mahjong
    rather seriously. Since weak players are shut out from the tokujou
    room, games in tokujou are qualitatively different from those in the
    joukyu and ippan rooms. Games in this room feel similar to those
    you’d experience at regular フリー (furii) mahjong parlors in Japan.
  12. 鳳凰 (houou; phoenix room)
    This is the highest-level room in Tenhou. In order to play in this
    room, you have to have all of the following: (1) a 七段 or higher rank,
    (2) a 2000 or higher R, and (3) a paid membership (¥ 540 yen = e 4
    = £ 3 per month). Satisfying the first two conditions can be really,
    really challenging.
    This is arguably one of the highest-level mahjong locales in the
    whole world. It is not uncommon for you to come across a houou-
    level player at a regular mahjong parlor in Japan. However, you usu-
    ally play against at most one houou-level player at a table, and the two
    other players at the table are either tokujou- or joukyu-level players.
    What is remarkable about games in the houou room is that you will
    be surrounded by three other houou-level players. It would be safe
    to say that no other public mahjong locale in the world — whether it
    is online or offline — could offer a comparable experience.4
    4 Perhaps the highest-level leagues in professional mahjong associations in Japan
    have players who are of comparable quality, but you have to become a profes-
    sional player to play at such leagues. Even after becoming a professional, you
    will need at least a few years to reach the highest league.
    2.3. READING THE STATISTICS 37
    2.3 Reading the statistics
    After you play 30 games or so, you may want to start paying atten-
    tion to the statistics shown on the right-hand side of the main page.5
    The upper half of the player statistics shows your statistics for the
    entire period, whereas the bottom half shows your statistics in the
    present month for a given type of game in a given room.
    2.3.1 Overall statistics
    The picture below show my old player statistics (upper half) back
    from when I had a 二段 rank. Let me explain how to read these statis-
    tics.
    Entire period (4-player games)
    first place
    second place
    third place
    fourth place
    bankruptcy
    win rate
    deal-in rate
    call rate
    riichi rate
    Below a player name is the expiration date of my premium mem-
    bership (17 November, 2015). When I started playing Tenhou on 17
    September, 2015, I bought a 60-day membership so I can play in the
    joukyu room. If you have just created a Tenhou account, the expira-
    tion date will be shown as today’s or tomorrow’s date, since we are
    given a 1-day premium membership when we open an account.6 Af-
    ter a day or two, it will turn into “—-/–/–” meaning that you do not
    have a premium membership.
    5 There is really no point in reading too much into the statistics when you have
    played only a few games; the sample size is too small to be meaningful.
    6 You need to have a premium membership to use Tenhou’s Windows client.
    38 CHAPTER 2. ADVANCED FEATURES OF TENHOU
    The box below the expiration date that reads 全期間 / 段位戦 4 人
    打ち indicates that the statistics below are for the entire period (not
    just this month) and for 4-player games (not 3-player games). Below
    that, we see that I had a 二段 rank, 565 points (the initial 400 points
    plus 165 points earned after I became 二段) out of the 800 points I
    need for promotion, and an R of 1987.
    Three columns below these display my statistics. The first col-
    umn shows my placement rates. I had come in first place 50% of the
    games, second place 32.5%, third place 7.5%, fourth place 10 %, and
    gone bankrupt 7.5% of the games. Ideally, you’d want your first place
    rate to be greater than your second place rate, your second place rate
    greater than your third place rate, etc.
    The middle column provides the following information. First, 対
    戦数 shows the number of games you have played. At this point, I had
    played 40 games. Second, 平均得点 shows the average score (with
    oka and uma) from all the games I have played. As I said before, this
    does not influence your R nor rank. Third, 平均順位 shows the aver-
    age placement. If you have obtained each of the four places equally,
    the average placement would be 2.5 ( 1n+2n+3n+4n
    4n = 2.5). Therefore,
    any values below 2.5 indicate that you are, on average, winning more
    than losing. The two rows that follow (shown in light gray) are rel-
    evant only if you play games in private rooms. Since I have only
    played ranking matches, they are left blank.
    The third column shows my statistics based on hand-level perfor-
    mance. First, 和了率 (houra rate; agari rate; win rate) is the number
    of hands you have won divided by the total number of hands you
    have played in all games.7
    7 The denominator includes hands where no one won.
    2.3. READING THE STATISTICS 39
    Second, 放銃率 (houjuu rate; deal-in rate) is the number of times
    you have fed the winning tile to an opponent’s hand divided by the
    total number of hands you have played. You would want this rate to
    be lower, but keep in mind that (1) sometimes you would be better
    off dealing into an opponent’s hand to secure your placement, and
    (2) sometimes you need to discard dangerous tiles (which would in-
    crease your deal-in rate, on average) in order to increase the chance
    of winning your hand (which would increase your win rate, on av-
    erage). The rule-of-thumb is that the difference between your win
    rate and deal-in rate (win rate - deal-in rate) should be at least 10
    percentage points. That is, if you have a high deal-in rate, you need
    your win rate to be higher. Likewise, if you have a low deal-in rate,
    it is OK to have a lower win rate as well.
    Third, 副露率 (fuuro rate; call rate) is the number of hands where
    you have called chii / pon / kan divided by the total number of hands
    you have played. Finally, 立直率 (riichi rate) is the number of riichi
    calls you made divided by the number of hands you have played.
    The ranking page on Tenhou8 has a table that summarizes the av-
    erage values of these statistics among players with different ranks
    (under the heading that reads 段位戦4人打ち平均戦績). You may
    want to compare your statistics with the average values among play-
    ers who share your rank or those who have higher ranks than you do.
    Figure 2.1 summarizes the average values of hand-level performance
    statistics for players in different ranks.
    We can see some interesting patterns here. The left-hand side
    panel compares average win rates (和了率) and deal-in rates (放銃
    率) for different ranks. Notice that the average win rate is relatively
    8 オンライン対戦麻雀 天鳳 / ランキング
    40 CHAPTER 2. ADVANCED FEATURES OF TENHOU0.10 0.15 0.20 0.25
    新人
    9級
    8級
    7級
    6級
    5級
    4級
    3級
    2級
    1級
    初段
    二段
    三段
    四段
    五段
    六段
    七段
    八段
    九段
    十段
    天鳳
    Player rank
    Average rates
    stats
    deal-in
    win0.15 0.20 0.25 0.30 0.35
    新人
    9級
    8級
    7級
    6級
    5級
    4級
    3級
    2級
    1級
    初段
    二段
    三段
    四段
    五段
    六段
    七段
    八段
    九段
    十段
    天鳳
    Player rank
    stats
    call
    riichi
    Figure 2.1: Average hand-performance statistics
    Note: These graphs show the hand-performance statistics reported in a table on the
    ranking page (オンライン対戦麻雀 天鳳 / ランキング) as of 20 December, 2015.
    constant across different ranks; once you pass the 新人 rank, it stays
    around 20-22 %.
    On the other hand, the average deal-in rate is steadily decreasing
    after players move from the kyu ranks into the dan ranks. It is around
    15% for almost all kyu rank players (except for 新人 and 1 級), but it
    keeps going lower and lower as players rise in the dan rank. The
    fact that high-dan players have lower deal-in rates on average is re-
    markable, considering that they are facing stronger opponents than
    low-dan players do. This pattern signifies the importance of defen-
    sive skills.
    Another interesting thing to notice on the left-hand side panel
    is that the average scores deteriorate once you move from 2 級 to 1
    級 (i.e., average win rate gets lower, and average deal-in rate gets
    higher).
    I can think of two reasons for why this happens. First, 1 級 is
    where most players start playing in the joukyu (upper-level) room,
    2.3. READING THE STATISTICS 41
    where average player skills are much higher than those in the ippan
    (lower-level) room. If a player who belongs to the lower-level room
    plays in the upper-level room, their performance will necessarily go
    down, making it look that 1 級 players are worse than 2 級 players
    even if they are not. Second, if you keep losing as a 初段 (first dan)
    player, you get demoted to 1 級 but you will never be demoted to 2
    級. This means that 1 級 players might actually be worse than 2 級
    players, on average.
    The right-hand side panel shows the average call rates (副露率)
    and riichi rates (立直率) for different ranks. The former is increasing
    as rank goes up, while the latter is decreasing, but the changes are
    rather gradual for both rates.
    42 CHAPTER 2. ADVANCED FEATURES OF TENHOU
    2.3.2 Monthly statistics
    The bottom-right part of the main page shows monthly statistics
    from games you have played in a given room. The box is a pull-
    down menu that lets you choose the room (一般, 上級, 特上, 鳳凰)
    and game type (East-only, East–South, with or without open tanyao,
    red fives, etc.). In the example below, the box reads 月間 / 上南 喰ア
    リ赤, which means the following: 月間 means monthly, 上 is short for
    上級 (joukyu)9, 喰アリ赤 means with open tanyao and red fives.
    Cumulative Average
    Scores
    Placement
    first place
    fourth place
    Below the box, you see the raw placement scores. In this example,
    17+11+3+4 = 35 戦 means that I have played 35 games this month,
    and I came in first place in 17 games, second place in 11 games, third
    place in 3 games, and fourth place in 4 games. R shown here (1987)
    should be the same as the R you see in the top part. 3382 位 means
    that R=1987 puts me in 3382nd place among all the active players on
    Tenhou.
    Two columns follow, where the left column shows the monthly
    cumulative values and the right column shows the monthly average
    values. In the first row that reads 得点 shows the monthly cumula-
    tive or average scores from 上南 喰アリ赤 games (after adding oka
    9 Likewise, 般 is short for 一般 (ippan), 特 is for 特上 (tokujou), 鳳 is for 鳳凰
    (houou).
    2.4. VIEWING GAMES 43
    and uma). In this example, my cumulative score is 727 from the 35
    games I played, which puts me in 106th place among players who
    have played 30 or more 上南 喰アリ赤 games this month. Similarly,
    my average score is 20.7 (= 727/35), which puts me in 5th place.
    Your placement for average scores will not be shown unless you have
    played 30 or more games of a given type in a given room in a given
    month.
    In the second row that reads 順位 shows cumulative and average
    placement from games. The cumulative placement is based on place-
    ment values (+30, +10, 10, or 30), whereas the average placement
    is based on raw placement (1, 2, 3, or 4). The 総合 (total) score is the
    sum of four placements: cumulative 得点, cumulative 順位, average
    得点, and average 順位. In this example, I earn 106th, 80th, 5th, and
    3rd places for these scores, so my total score is 106+80+5+3 = 194
    (the lower, the better), which puts me in 12th place among all the
    players who have played 30 or more 上南 喰アリ赤 games this month.
    At the bottom, you see トップ率 (first place rate), ラス率 (fourth place
    rate), and 連対率 (first or second place rate) for 上南 喰アリ赤 games
    this month.
    2.4 Viewing games
    2.4.1 Game replay (牌譜)
    Tenhou keeps the record of all the games played there, giving each
    game a unique URL. You can easily take a look at any of the last 40
    games you have played on the 牌譜 (haifu; game record) tab on the
    main page. Click on any of the 牌譜 link shown in the 牌譜 tab to start
    a replay of the game. You can choose to view the game from any of
    the four players’ viewpoint, not to show the hands of the other three
    players, or to go back and forth between turns / hands, etc. When we
    44 CHAPTER 2. ADVANCED FEATURES OF TENHOU
    play mahjong, we often wonder what the opponents are doing (e.g.,
    what are their waits? are they doing honitsu?, etc.). You can find
    out the answers to these questions after the game by taking a look at
    the game record.
    If you would like to have someone take a look at a particular game
    you played to ask for their opinions, you need to find the unique URL
    assigned to the game you want to show. You can find out the URLs of
    the last 40 games by going to the 牌譜の管理 menu from the メニュー
    pull-down on the main page. Clicking on 牌譜の管理 will open a new
    pop-up screen.
    You can choose to open a game replay in the current window (こ
    のウィンドウで開く), in a new pop-up window (新しいポップアッ
    プで開く), or in a new window (新しいウィンドウで開く) from the
    pull-down menu above. Once you are happy with your choice, click
    on the 再生 (replay) link next to the game you want replayed. You
    will be taken to a page that looks like the one you saw after clicking
    on the Play button on the top page of Tenhou. You can now find out
    the URL assigned to the game in the URL field of your browser.
    To start a replay, click on a link that reads » Flash 版牌譜ビューアで
    開く shown at the bottom of the page. Clicking on the HTML+JS 版
    牌譜ビューアで開く link will also work, but this one is the low-quality
    picture version with limited options.
    2.4. VIEWING GAMES 45
    2.4.2 Spectating games (観戦)
    You can watch games played in the 特上 (tokujou; advanced)
    and the 鳳凰 (houou; phoenix) rooms in quasi-real time (with a five-
    minute delay). Click on the 観戦 (kansen; spectating) tab from the
    main page and you will see the list of games you can watch. Click
    on one of the player name links to start spectating the game from the
    chosen player’s viewpoint.
    Part II
    Basic Tile Efficiency
    46

Chapter 3
Riichi mahjong basics
3.1 Learning strategies
Mahjong is a game of skill and luck. There is a set of strategy
principles you can learn to improve your skills, but acquiring skills is
neither necessary nor sufficient to win a game. On the contrary, with
luck, an unskilled player can easily defeat strong players in mahjong.
At least in the short run, game outcomes are governed more by luck
than by skills.1 However, learning strategy principles is crucial to
improve your performance in the long run. Moreover, you will be
able to enjoy the game in greater depth once you understand these
principles.
Because of the probabilistic nature of the game, making the best
choice does not always lead to the best outcome. The best choices
are those that lead to the best outcome, on average. An evaluation of
our choices thus requires a probabilistic (i.e., statistical) assessment of
different options. For example, consider the following hand.
a $$L
What would you discard?
This hand becomes ready to win if you discard or . Let’s com-
pare the two choices.
1 An interesting question would be: how short is the “short” run here. That is,
how many games do we need in order to discern a strong player from weak
players? Studies show that we would need at least 100 games or so to have a
reliable estimate of our skill levels. Given that EMA tournaments usually have
only 8 games, winning at these tournaments requires quite a bit of luck.
3.1. LEARNING STRATEGIES 49
• Discard ) you wait for (2 kinds–8 tiles)
• Discard ) you wait for (2 kinds–4 tiles)
Which discard choice is better? Although both of the two choices
yield a 2-way wait, waiting for is much better than waiting
for , probabilistically speaking. With the wait, there are
four tiles of and another four tiles of to win on, leaving at most
eight winning tiles.2 With the wait, on the other hand, you
have already used up two tiles of and two tiles of yourself,
leaving at most four winning tiles. It is clearly better to choose the
wait over the wait, because that will give you a higher
probability of winning this hand.
It is possible that, after you decided on the wait, your op-
ponents end up not discarding or at all, while discarding lots of
. This is the kind of thing that will happen often in mahjong (or
in any game of luck, for that matter). When things like this happen,
do not think that you made a bad call; you didn’t. You made the right
choice, but you were just unlucky. When we experience this kind of
bad luck, we just need to keep calm and carry on.
Before discussing a practical method of maximizing tile efficiency
in the next chapter, I will discuss some basic principles of tile effi-
ciency in this chapter. In doing so, I introduce several key terms we
use in later chapters. I will also provide the original Japanese term
for each (shown in this font). I do so because you may find these
Japanese terms used in some online strategy discussions in English.
2 Of course, the number of winning tiles could be smaller than eight if some of
them have already been discarded.
50 CHAPTER 3. RIICHI MAHJONG BASICS
3.2 Basic building blocks
3.2.1 Tiles
Mahjong tiles can be classified into two categories — number tiles
and honor tiles.
Number tiles
Number tiles
Cracks (characters) Manzu ȷff
Dots (circles) Pinzu
Bamboos Souzu a
We further classify number tiles into simples (tanyao hai; tiles be-
tween 2 and 8) and terminals (yaochu hai; 1 and 9). They are dif-
ferentiated because they serve different yaku and generate different
minipoints (fu).
It has become quite common to include some red five tiles. For
example, most games on Tenhou have one red five tile in each suit,
. These tiles are included in place of regular fives; we have
three regular fives and one red five in each suit. Red fives are treated
as dora regardless of the dora indicator. When a 4 in a given suit is
the dora indicator, the red five in that suit will be a double dora tile.
3.2. BASIC BUILDING BLOCKS 51
Honor tiles
Honor tiles
Dragon tiles # $ %
White (haku) Green (hatsu) Red (chun)
Wind tiles ffl ! "
East (ton) South (nan) West (sha) North (pei)
Some honor tiles are value tiles (fanpai / yakuhai); we get one han
if we collect three identical value tiles. All dragon tiles are value tiles
regardless of the round and seating. On the other hand, the value
status of wind tiles depends on the round and the seating. East tiles
are value tiles for everyone during the East round, and South tiles are
value tiles for everyone during the South round. In addition, each
player gets their own seating wind as a value tile. For example, West
tiles are value tiles only for the West player, but they are valueless
wind tiles (otakaze) for other players.
52 CHAPTER 3. RIICHI MAHJONG BASICS
3.2.2 Group (mentsu)
One of the major goals in playing mahjong is to win a hand.3 To
win a standard hand, we need to complete four groups (mentsu) and
one head (atama; final pair).4 Groups can be classified into two kinds
— run and set.5
• Run (shuntsu; chow / sequence) is a set of three consecutive
number tiles: e.g., ff, .
• Set (kotsu; pung / triplet) is a set of three identical tiles: e.g.,
, $$$.6
3.2.3 Ready and n-away
We say a hand is ready (tenpai) when the hand can be complete
with one more tile. For example, the following hand is ready.
Ready hand
a%%%
This hand becomes complete with either or . We say that this
hand waits for .
3 Another important goal is not to deal into an opponent’s hand. See Chapter 8
for discussions of defense strategies. However, the most important goal of all
is to win a game. Winning a hand and playing defense are merely two means
to this end. See Chapter 10 for more discussions of this.
4 There are three exceptions to this; chiitoitsu (Seven Pairs), kokushi musou
(Thirteen Orphans), and nagashi mangan (All Terminals and Honors Discard)
do not require four groups and one head.
5 EMA rules refer to run as “chow” and set as “pung.” I realize that my use of
different terminology here might be confusing at first, but I hope you will get
used to it soon.
6 Technically speaking, there is a third type of groups, namely quad (kantsu;
kong), a set of four identical tiles. We treat quads as a variant of sets. See
Section 9.3 for discussions on this.
3.2. BASIC BUILDING BLOCKS 53
We say a hand is 1-away from ready (1-shanten) when the hand
can become ready with one more tile. For example, the following
hand is 1-away from ready.
1-away hand
a%%%
This hand becomes ready if you draw any of . We say
this hand accepts (5 kinds–16 tiles) as any of them can
make this hand advance from 1-away to ready. Tile acceptance (ukeire)
refers to the kinds and the number of tiles a hand can accept. Other
things being equal, having a 1-away hand with greater tile acceptance
is better than having one with smaller tile acceptance.
More generally, we say a hand is n-away from ready (n-shanten)
when the hand can be ready with n more steps. For example, the
following hand is 2-away from ready.
2-away hand
aa%%%
This hand accepts all the tiles that the 1-away hand above accepts
(), plus seven additional kinds of tiles a.7
The hand will become 1-away if any of these tiles gets drawn.
A hand can also be 3-away, 4-away, 5-away, or 6-away from ready.8
In practice, however, there is not much point in distinguishing 3-
away hands from 4-away (or worse) hands. You thus need to be able
7 will make this hand 1-away for chiitoitsu (Seven Pairs).
8 6-away happens when a hand has no pair, in which case it takes 6 more tiles to
make it ready for chiitoitsu.
54 CHAPTER 3. RIICHI MAHJONG BASICS
to distinguish between four kinds of hands — ready hands, 1-away
hands, 2-away hands, and 3-away or worse hands.
Tile acceptance shrinkage
As n gets smaller and the hand gets closer to completion, the
kinds and the number of tiles it can accept will necessarily get smaller.
Consider the three stages of a hand we have seen above.
• When 2-away, it accepts: a.
• When 1-away, it accepts: .
• When ready, it waits for: .
Tile acceptance is minimized when the hand is ready. Note also that
it is virtually minimized when it is 1-away. This is because with a
ready hand you can utilize not only the tiles you draw but also the
tiles discarded by others to complete the hand. With n-away hands,
however, you have to rely (almost) solely on the tiles you draw your-
self to advance your hand.9 Therefore, in choosing a discard from a
2-away hand, we should try not to make for a 1-away hand with too
small tile acceptance.
Advancing your hand
To win a hand, we need to advance our hand by reducing the n of
an n-away hand until it is ready. When a hand is 2-away, we should
aim to make the hand 1-away. When a hand is 1-away, we should aim
to make the hand ready. For example, consider the following hand.
9 Melding (calling pon / chii) is not always possible. For example, the 2-away
hand above can accept if you draw one, but you can neither pon nor chii .
3.2. BASIC BUILDING BLOCKS 55
2-away vs. 1-away
ȷffff a $$$
What would you discard?
Discarding makes the hand 2-away, whereas discarding either ff
or makes the hand 1-away. You should thus discard ff or to
make the hand 1-away. Reverting a 1-away hand to 2-away makes
sense only in some exceptional cases where tile acceptance at 1-away
becomes unbearably small (i.e., fewer than 2 kinds). With this hand,
the hand will be able to accept (3 kinds–12 tiles) when it
becomes 1-away.
3.2.4 Protoruns (taatsu)
Of the two kinds of groups, it is easier to complete a run than
to complete a set. There are only four identical tiles, and complet-
ing a set requires that you collect three out of the four identical tiles.
Therefore, we usually prioritize runs over sets in advancing a hand.
A pair of tiles that can become a run with one more tile is called a
protorun (taatsu). There are three types of protoruns, summarized
in Table 3.1.
Table 3.1: Types of protoruns
Name Japanese Example Wait Acceptance
side wait ryanmen - 2 kinds–8 tiles
closed wait kanchan 1 kind–4 tiles
edge wait penchan a 1 kind–4 tiles
As we can see in the table, a side-wait (ryanmen) protorun can
56 CHAPTER 3. RIICHI MAHJONG BASICS
accept twice as many tiles as a closed-wait (kanchan) protorun or
an edge-wait (penchan) protorun can. Therefore, building side-wait
protoruns is the key to advancing a hand. Winning tiles of side-wait
protoruns are often denoted with a hyphen in the middle, such as
- or -.10
Closed wait vs. edge wait
There is no difference in the kinds and the number of tiles ac-
cepted by closed-wait and edge-wait protoruns; they both accept 1
kind–4 tiles. However, closed-wait protoruns are superior to edge-
wait ones because they can more easily evolve into a side-wait pro-
torun.
A closed-wait protorun can evolve into a side-wait protorun in
just one step. For example, a protorun can become a side-wait
one if you draw and discard .
)
draw
On the other hand, it requires two steps for an edge-wait protorun to
evolve into a side-wait protorun. For example, a protorun can
become a side-wait one if you draw first and then .
) )
draw draw
Value ranking of protoruns
side wait > closed wait > edge wait
10 Note that - wait means the winning tiles are and , not through .
3.2. BASIC BUILDING BLOCKS 57
Tile versatility
Some tiles are more versatile than others. For example, number
tiles are more versatile than honor tiles because honor tiles can never
form a run. Moreover, we can rank order the versatility of number
tiles based on the types of protoruns they can form.
Number tiles between 3 and 7 are the most versatile. This is be-
cause each of them can form a protorun with four kinds of number
tiles. For example, can form a protorun with , , , and .
Two out of the four resulting protoruns will be side wait.
2 and 8 are less versatile. They can form a protorun with only
three kinds of number tiles. For example, can form a protorun
with , , and . Only one out of the three resulting protoruns is
side wait.
Terminals (1 and 9) are the least versatile. They can form a pro-
torun with only two kinds of tiles. For example, can form a pro-
torun only with and . Neither of the two resulting protoruns is
side wait.
Versatility ranking of tiles
3–7 tiles > 2, 8 tiles > 1, 9 tiles > honor tiles
Applying the same logic, we can also rank order the versatility of
closed-wait protoruns. For example, a closed-wait protorun
can become a side-wait one only if we draw . Likewise, a closed-
wait protorun can become a side-wait one only if we draw .
However, a closed-wait protorun can become a side-wait one if
we draw or . Clearly, is more versatile than or .
58 CHAPTER 3. RIICHI MAHJONG BASICS
Versatility ranking of closed-wait protoruns
35, 46, 57 > 13, 24, 68, 79
3.2.5 Pairs (toitsu)
A set of two identical tiles is called a pair (toitsu). Pairs can per-
form several different roles. A pair can be the head (final pair) of a
hand, a protoset (a candidate for a set), or a component of chiitoitsu
(Seven Pairs).
Building the head
Any hand — including Thirteen Orphans and Seven Pairs — re-
quires the head to be complete. Since building the head is much eas-
ier than building a group, we usually don’t worry too much about
the head. For example, consider the following hand.
Hand with no head
ff a
This hand currently lacks the head and the wait is not very good.
The hand is complete only with a (1 kind–3 tiles). However, if we
draw any of ȷ (12 kinds–41 tiles), the
wait will be significantly improved. For example, if we draw and
discard a, the hand becomes:
ff
This hand is now waiting for - (3 kinds–9 tiles). When a
3.2. BASIC BUILDING BLOCKS 59
hand is missing the head, it is often the case that the wait gets signif-
icantly improved quite easily.
3.2.6 Pairs and sets
Another important role a pair can play is to work as a candidate
for a set. Especially when a hand has two pairs, we can count on
one of the two pairs to become the head while the other becomes a
set. In other words, the value of pairs is maximized when there are
two (and only two) pairs in a hand. Let’s see why this is the case by
comparing hands with one, two, and three pairs.

  1. Hand with one pair
    a"
    This 2-away hand has one pair: . This pair is not very useful as
    a candidate for a set for two reasons. First, if we draw another ,
    we will complete a set but then we will lose the head at the same
    time. The hand will still be 2-away from ready after all. Second, the
    probability of drawing another is not very high because there are
    only two tiles left.
    What if a hand has two pairs? Suppose we drew and discarded
    ", as follows.
  2. Hand with two pairs
    a
    This hand is also 2-away, but it has two pairs: and . Each
    of these pairs is now functioning as an effective candidate for a set.
    Whenever one pair becomes a set, the other pair becomes the head.
    Drawing or will advance this hand from 2-away to 1-away.
    60 CHAPTER 3. RIICHI MAHJONG BASICS
    Moreover, whereas the hand with one pair was able to accept two
    tiles of , the hand with two pairs can accept four tiles (two of
    and two of ). The probability of drawing any one of four tiles
    is obviously higher than the probability of drawing any one of two
    tiles. In general, for each additional pair in a hand, tile acceptance
    increases by two.
    What if a hand has three pairs? Suppose we draw , as follows.
  3. Hand with three pairs
    a Draw
    If we keep the second and discard the a or the , the hand has
    three pairs. However, keeping three pairs in a hand is inefficient. Re-
    call that each additional pair increases tile acceptance by two tiles. In
    this case, keeping a pair of means that the hand can accept two
    additional tiles of . However, doing so comes with a cost. Keep-
    ing three pairs by discarding the a means the hand can no longer
    accept (2 kinds–8 tiles). The net tile acceptance gain will be
    negative (2 8 = 6). Similarly, keeping three pairs by discarding
    the means the hand can no longer accept (4 tiles). Therefore,
    discarding a to maintain two pairs is the most efficient.
    What we have seen so far is generalizable beyond the current ex-
    amples. As long as we intend to keep the hand closed (i.e., not calling
    pon or chii), we should avoid having three pairs in a hand. Having
    three pairs makes for the weakest form, whereas having two pairs
    makes for the strongest form.11
    11 What if there are four or more pairs? Whenever a hand has four pairs, it is
    2-away from ready for chiitoitsu (Seven Pairs). It may be faster to pursue
    chiitoitsu than pursuing a standard hand in such cases.
    3.2. BASIC BUILDING BLOCKS 61
    Value of pairs: closed hand
    2 pairs > 1 pair, 4 pairs > 3 pairs
    Open hand
    There is an important caveat to the above rule. When we intend
    to call pon, having three pairs is actually better than having two pairs.
    This is because the hand will become a two-pair hand after we call
    pon once. For example, consider the following hand.
    Two pairs vs. three pairs
    a %% %Dora
    What would you discard?
    We would definitely intend to call pon on %. Anticipating that, we
    should discard to keep three pairs in this case rather than dis-
    carding to have two pairs. After calling pon on %, we will have a
    choice between discarding or .
    a %M%
    a %M%
    In either case, the hand will have two pairs after calling pon.
    Value of pairs: open hand
    3 pairs > 2 pairs
    62 CHAPTER 3. RIICHI MAHJONG BASICS
    3.2.7 Perfect n-away
    Perfect 1-away
    When a 1-away hand has two side-wait protoruns and two pairs,
    it is called perfect 1-away.
    Perfect 1-away
    a###
    The hand above is an example of perfect 1-away. It is called “perfect”
    because this hand can become ready either by calling chii, calling
    pon, or drawing a tile to complete a run or a set, and no matter how a
    hand becomes ready, you will always have the option to choose side
    wait as the final wait.
    Perfect 2-away
    One step prior to achieving perfect 1-away, we may get a perfect
    2-away hand. Perfect 2-away is made up with three side-wait pro-
    toruns and three pairs, as follows.
    Perfect 2-away
    aa###
    When a perfect 2-away hand becomes 1-away, it can always be perfect
    1-away (unless you choose not to, for some reason). However, not all
    perfect 1-away hands evolve from a perfect 2-away hand.
    3.2. BASIC BUILDING BLOCKS 63
    3.2.8 Putting things all together: an example
    Let’s see some hand examples that illustrate how we can apply
    the tile efficiency logics we have learned so far. Consider the follow-
    ing 2-away hand.
    Advancing a hand 1
    ff
    Draw
    What would you discard?
    The hand now has three pairs, and we should avoid it. In order to re-
    duce the number of pairs in this hand from three to two, our discard
    candidates should be , , or . Which one should we choose?
    Recall that a closed-wait protorun of 57 is stronger than a closed-
    wait protorun of 24 or an edge-wait protorun of 89. Therefore, it is
    OK to cut down the ff shape to ff by discarding . This is
    because ff can become a side-wait protorun relatively easily. On
    the other hand, the shape and the shape are both
    weak; the first can become a side-wait protorun only if we draw ,
    and the second one will never become a side-wait protorun in one
    step. Therefore, both and should be kept as a can-
    didate for the head or a group rather than making them into weak
    closed-wait protoruns.
    Let’s say we discard , and then we draw , resulting in the
    following hand.
    Advancing a hand 2
    ff
    Draw
    What would you discard?
    64 CHAPTER 3. RIICHI MAHJONG BASICS
    Now that we have a side-wait protorun ff, we should discard .
    Let’s say we draw a, resulting in the following hand.
    Advancing a hand 3
    ff a
    Draw
    What would you discard?
    This hand is now 1-away from ready, and our discard choice is be-
    tween and . Both tiles are equally useless from our perspective,
    and so we will eventually discard them both. The question is which
    one we should discard first. Recall that a 4 is more versatile than an
  4. This means that in this hand may later become dangerous for
    the opponents; we should thus discard now rather than later.
    Let’s say we draw after that, resulting in the following hand.
    Advancing a hand 4
    ffa
    Draw
    What would you discard?
    The hand is now ready. We should discard and call riichi. If we
    win on , we can claim riichi, pinfu, and sanshoku (Mixed Triple
    Chow), giving us 7700 points.12
    12 We will discuss scoring and yaku more extensively in later chapters.
    3.3. COMPLEX SHAPES 65
    3.3 Complex shapes
    The three basic types of tile blocks we have covered so far —
    groups (runs and sets), protoruns (side wait, closed wait, and edge
    wait), and pairs — form the basis of any standard mahjong hands.13
    When a hand has some tiles that do not constitute any of these three
    shapes, we treat them as floating tiles. For example, and in
    the following hand are both floating tiles.
    Hand with floating tiles

    In addition to these basic blocks, we often come across complex
    shapes that are made up of two or more groups, protoruns, pairs,
    and floating tiles combined. It is useful to comprehend such com-
    plex shapes as they are rather than breaking them up into smaller
    parts. We will discuss three-tile complex shapes and four-tile com-
    plex shapes in turn.
    3.3.1 Three-tile complex shapes
    There are two kinds of three-tile complex shapes — double closed
    shape and protorun plus one shape.
    13 Standard hands are those with four groups and one head. Non-standard hands
    are chiitoitsu (Seven Pairs) and kokushi musou (Thirteen Orphans).
    66 CHAPTER 3. RIICHI MAHJONG BASICS
    Double closed (ryankan) shape
    When two closed-wait protoruns are combined, we have a dou-
    ble closed (ryankan) shape. There are five different patterns in each
    suit, as follows.
    a
    a
    Each shape accepts as many as 2 kinds–8 tiles. For example,
    accepts (4 tiles) and (4 tiles). This is twice as many as the
    number of tiles an isolated closed-wait protorun can accept.
    Sometimes a double closed shape is embedded within a tile block,
    making it difficult to detect it. For example, consider the following
    1-away hand.
    Hand with a double closed shape
    Red
    ffaa Draw
    What would you discard?
    Before drawing , the hand was already in a very good shape. It was
    perfect 1-away, accepting any of ȷa (6 kinds–19 tiles).
    The question is whether we should keep and discard instead.
    Notice that, if we keep , we have a double closed shape .
    This is because the block can be split into
    and . If we keep and discard , the hand is still 1-away
    from ready, accepting ȷ (5 kinds–19 tiles). The benefit of
    discarding to keep the double closed shape is that the hand can
    3.3. COMPLEX SHAPES 67
    always be pinfu when it is ready. On the other hand, discarding
    means that the hand may become a yaku-less hand when drawing
    or a.
    Double closed shapes are particularly useful when a hand is rel-
    atively far from ready (2-away or worse). As a hand advances, how-
    ever, its usefulness diminishes because this block requires three (not
    two) tiles even though it is not a complete group. Moreover, it will
    ultimately become a single closed-wait protorun when this block re-
    mains incomplete when the hand is ready. Therefore, we should not
    rely too much on a double closed shape. For example, consider the
    following two hands.
    %% Draw
    ff Draw
    Both hands are 1-away from ready and both contain a double
    closed shape in souzu (bamboos) tiles. Maintaining the double closed
    shape in these cases will not be ideal. It is true that, if the hand be-
    comes ready by drawing or first, each of the hands makes for
    a good-wait ready hand. However, if the first hand becomes ready
    by calling pon on % or the second hand becomes ready by drawing
    or first, they only make for a closed-wait ready hand.
    Therefore, when we draw a tile next to the head, creating a side-
    wait protorun, we should keep it and break the double closed shape
    instead. In the first example above, as we draw that creates a side-
    wait protorun , we should keep it and discard the instead.
    68 CHAPTER 3. RIICHI MAHJONG BASICS
    In the second example above, as we draw that creates a side-wait
    protorun , we should keep it and discard instead.
    Protorun plus one shape
    As we saw with the first example in Section 3.2.8, we often come
    across a tile combination such as ff that is made up with one
    protorun plus one floating tile (ff + ).14 Depending on the type
    of protoruns, we can classify protorun plus one shapes into three
    types, as summarized in Table 3.2.
    Table 3.2: Types of protorun plus one shapes
    Name Example Wait Acceptance
    side wait +1 - 3 kinds–10 tiles
    closed wait +1 2 kinds–6 tiles
    edge wait +1 a 2 kinds–6 tiles
    A protorun plus one can accept two additional tiles that an iso-
    lated protorun cannot. This is because these blocks can now be a
    candidate for a set as well as for a run.
    Breaking a protorun plus one can be inefficient. For example, if
    we break a closed wait plus one shape into an isolated pair (i.e., dis-
    card from ), the tile acceptance decreases from 6 to 2; it
    can accept only (1 kind–2 tiles). Similarly, if we break it into an
    isolated protorun (i.e., discard from ), the tile acceptance
    decreases from 6 to 4; it can accept only (1 kind–4 tiles). With this
    in mind, consider the following hand.
    14 Alternatively, we can think of these combinations as a pair plus one + ff.
    3.3. COMPLEX SHAPES 69
    Protorun plus one
    ffa
    Draw
    What would you discard?
    Discarding or ff to break the protorun plus one ff is ineffi-
    cient here. Discarding decreases tile acceptance by two, and dis-
    carding ff decreases tile acceptance by four. Moreover, discarding
    ff leaves three pairs in this hand, which should be avoided. Discard-
    ing is much more efficient.
    Sometimes we have to make a choice between multiple protorun
    plus one shapes, just like we did in examples in Section 3.2.8. Con-
    sider the following hand. What would you discard?
    Multiple protoruns plus one
    ȷ ""
    What would you discard?
    There are two protorun plus one shapes in this hand: ȷ and
    . We have to break one of the two into either an isolated Pair
    or an isolated protorun, because the other parts of this hand are more
    or less self-sufficient. Which one should we choose?
    When choosing between which protoruns plus one to break, pri-
    ority should be given to the weaker one. Since the side-wait pro-
    torun is much stronger than the closed-wait protorun ȷ, we
    should prioritize the latter and maintain ȷ. In other words, the
    side-wait protorun is so strong that we do not need to provide
    a cover by maintaining the “plus one” tile, . On the other hand,
    the closed-wait protorun ȷ is weaker so we should cover it by
    keeping another as a back-up. You should thus discard .
    70 CHAPTER 3. RIICHI MAHJONG BASICS
    3.3.2 Four-tile complex shapes
    Among several different kinds of four-tile complex shapes, we
    will focus on those that are made up of one group and one floating
    tile. There are three variants of this kind — stretched single, bulging
    float, and skipping.
    Stretched single (nobetan) shape
    A set of four consecutive tiles such as is called a stretched
    single (nobetan) shape. Stretched single shapes are very useful both
    when a hand is ready and when a hand is 1-away or worse.
    When a stretched single shape is in a ready hand, that part forms
    the wait of the hand. For example, the following hand is ready, wait-
    ing for .
    Ready hand with a stretched single shape
    %%%
    In a ready hand, the stretched single shape can be thought of as a
    candidate for the head ( or ) and a candidate for a run (
    or ). For example, if we win this hand on , then becomes
    the head, and becomes a run. On the other hand, if we win
    this hand on , then becomes the head, and becomes a
    run.
    Another important role that a stretched single shape can play is
    to work as a candidate for two runs. When a hand is 1-away or worse,
    we can count on a stretched single shape to produce two runs. For
    example, consider a stretched single shape . If we draw ,
    we will have a side-wait protorun in addition to a complete run
    3.3. COMPLEX SHAPES 71
    . Similarly, if we draw , we will have a side-wait protorun
    in addition to a complete run . Moreover, if we draw
    or , we will have a 3-way side-wait shape (waiting for
    --) or (waiting for --).
    There are six patterns of stretched single shapes, from 1234 through
  5. Table 3.3 summarizes the tiles each shape can accept to produce
    various waits.
    Table 3.3: Types of stretched single shapes
    Shape 3-way 2-way 1-way Pair Acceptance
    ȷ 6 kinds–20 tiles
    ȷ ff 7 kinds–24 tiles
    ȷ ff ȷ 8 kinds–28 tiles
    ȷff ȷ ff 8 kinds–28 tiles
    ȷff ȷ ff 7 kinds–24 tiles
    ȷff ff ȷ 6 kinds–20 tiles
    As we can see, the middle two ones — 3456 and 4567 — are the
    most versatile. They can accept two different tiles to produce a 3-way
    wait (27 or 38), two different tiles to produce a 2-way side wait (45 or
    56), and two different tiles to produce a 1-way wait (18 or 29 to pro-
    duce a closed wait). The 3456 and 4567 shapes are the most valuable
    of all four-tile shapes, and we should not lightly break such shapes
    when a hand is far away from ready. With this in mind, consider the
    following 2-away hand.
    72 CHAPTER 3. RIICHI MAHJONG BASICS
    2-away hand with a stretched single shape
    ȷ a
    What would you discard?
    It is true that discarding or ȷ would lead to the greatest tile ac-
    ceptance (7 kinds–24 tiles) temporarily. However, doing so is too my-
    opic. If we do that, all the remaining protoruns will be closed-wait or
    edge-wait ones. We should rather discard to keep the 3456 shape,
    which we can expect to produce two side-wait protoruns later. The
    resulting tile acceptance (6 kinds–20 tiles) is not much smaller, either.
    Four-tile complex shapes 1: nobetan
    Try to keep a stretched single shape if a hand has one. In partic-
    ular, 3456 and 4567 should be kept until the hand becomes ready
    or 1-away from ready.
    Bulging float (nakabukure) shape
    When we have a floating tile in the middle of a run (e.g., ),
    we have a bulging float (nakabukure) shape. Bulging float shapes
    are quite good at producing side-wait protoruns. Any bulging float
    shapes from 2334 through 6778 can accept four kinds of tiles to pro-
    duce a side-wait protorun and a complete run. Take , for
    example. It can produce a side-wait protorun and a complete run if
    we draw any of ȷ . With this in mind, consider the following
    2-away hand.
    3.3. COMPLEX SHAPES 73
    Hand with a bulging float shape

    What would you discard?
    Discarding to break the bulging float shape is not ideal. Although
    doing so increases tile acceptance temporarily, the hand will be filled
    with closed-wait protoruns. Alternatively, you should discard to
    maintain the bulging float shape.
    That being said, when this shape remains as is when a hand is
    ready, it does not make for a good wait. For example, consider the
    following ready hand.
    Ready hand with a bulging float shape
    "%%% Draw
    What would you discard?
    Discarding " to keep the bulging float shape makes the
    wait of this hand pretty bad. It is waiting for , but we are already
    using two of it in the hand, leaving only two winning tiles. We should
    rather discard to wait for “.
    Four-tile complex shapes 2: nakabukure
    Try to keep a bulging float shape until a hand becomes 1-away.
    74 CHAPTER 3. RIICHI MAHJONG BASICS
    Skipping shape
    When we have a floating tile two tiles away from a run, we have
    a skipping shape. For example, in a shape ȷff , is floating
    two tiles from a run ȷff. in a skipping shape is more valu-
    able than isolated , because it increases the kinds of tiles the hand
    can accept to produce a protorun or a 3-way side-wait shape. Table
    3.4 summarizes all the skipping shapes and the tiles each shape can
    accept.
    Table 3.4: Types of skipping shapes
    Shape 3-way 2-way 1-way Pair Acceptance
    ȷ 4 kinds–14 tiles
    ȷ ff 5 kinds–18 tiles
    ȷff 6 kinds–22 tiles
    ȷff ȷ 6 kinds–22 tiles
    ff ȷ ff 5 kinds–18 tiles
    ȷ ff 5 kinds–18 tiles
    ȷ ff ȷ 6 kinds–22 tiles
    ff ȷ ff 6 kinds–22 tiles
    ȷ ff ȷ 5 kinds–18 tiles
    ȷff ff 4 kinds–14 tiles
    Bearing in mind that of ȷff is more valuable than iso-
    lated , consider the following hand.
    3.3. COMPLEX SHAPES 75
    Hand with a skipping shape
    ffa%%% Draw
    What would you discard?
    We should keep and discard instead. This is because is a
    part of a skipping shape , but is an isolated floating tile.
    As we can see in Table 3.4, skipping shapes with a terminal tile
    (1345 and 5679) are also valuable. The 1 of 1345 and the 9 of 5679 can
    accept more tiles than an isolated 2 or 8 (let alone than an isolated 1
    or 9).
    76 CHAPTER 3. RIICHI MAHJONG BASICS
    3.4 Waits
    There are five basic wait patterns, as summarized in Table 3.5.
    More complicated wait patterns can emerge when some of these five
    basic patterns are combined.
    Table 3.5: Five basic waits
    Name Japanese Example Wait Acceptance
    side wait ryanmen - 2 kinds–8 tiles
    dual pon wait shanpon 2 kinds–4 tiles
    closed wait kanchan a 1 kind–4 tiles
    edge wait penchan 1 kind–4 tiles
    single wait tanki 1 kind–3 tiles
    As we can see in the table, side wait is the strongest of all the basic
    waits in terms of the kinds and the number of tiles to win on. Single
    wait appears to be much worse than others, but single-wait hands
    tend to have many possibilities of improving the wait and/or scores
    further. Moreover, single wait of an honor tile has a relatively high
    chance of winning it by ron.
    Stretched single wait and semi side wait
    Table 3.6 summarizes two wait patterns, each of which can be
    thought of as a combination of some basic wait patterns. As I men-
    tioned before, a stretched single shape in a ready hand forms a 2-way
    single wait. It is a decent wait pattern, as the number of tiles to win
    on (2 kinds–6 tiles) is twice as big compared with a regular single
    wait.
    3.4. WAITS 77
    Table 3.6: Stretched single wait and semi side wait
    Name Example Waits Acceptance
    stretched single wait 2 kinds–6 tiles
    semi side wait - 2 kinds–6 tiles
    However, stretched single wait should not be confused with side
    wait for a few reasons. First, the number of tiles a 2-way stretched-
    single-wait hand can win on is at most 6, whereas it is 8 for a 2-way
    side-wait hand. The difference between 6 and 8 is non-trivial. Sec-
    ond, stretched single wait is still a variant of single wait, which means
    two things. On the one hand, we cannot claim pinfu when the wait is
    stretched-single wait. For example, the following hand has no yaku
    and hence we cannot win it by ron without calling riichi.
    ȷ
    On the other hand, we get 2 minipoints (fu) with a stretched single
    wait. For example, if we win the following hand by drawing , we
    get 40 minipoints (20 base minipoints + 8 for a concealed set of honor
    tiles + 2 for self-draw + 2 for single wait = 32, rounded up to 40).15
    ȷ %%%
    When we have a side-wait protorun right next to a pair (e.g., 1123,
    2234, 7899, etc.), we call it semi side wait. We distinguish this from
    regular side wait for two reasons. First, the number of tiles to win
    on is smaller (6 rather than 8) because we are already using 2 of the
    15 We will discuss methods of scoring and minipoints calculations extensively in
    Chapter 6.
    78 CHAPTER 3. RIICHI MAHJONG BASICS
    8 winning tiles in our hand. Second, we can treat this wait pattern
    either as single wait or as side wait, depending on which interpre-
    tation gives us a greater score. For example, consider the following
    hand.
    ȷ
    We will treat the wait in this hand as side wait because that will give
    us pinfu. However, consider the following hand that has the exact
    same wait pattern: .
    ȷ %%%
    If we win this hand by drawing , we will treat the wait as single
    wait: + , which will give us 40 minipoints. If we treated
    the wait as side wait: + , we would get only 30 minipoints.
    Of course, if we win this hand on , we cannot think of the wait as
    single wait (because it is not). Similarly, if we win it by ron, it does
    not make a difference if it is side wait or single wait (either way we
    get 40 minipoints).
    3.4. WAITS 79
    3-way side wait
    When a side-wait protorun is combined with an adjacent run, we
    get a regular 3-way side-wait pattern. There are only three of this
    kind, summarized in Table 3.7.
    Table 3.7: Regular 3-way side wait
    Example Wait Acceptance
    ȷ --ff 3 kinds–11 tiles
    -- 3 kinds–11 tiles
    a -- 3 kinds–11 tiles
    When we have a stretched single shape or semi side-wait shape
    combined with an adjacent run, we also get a 3-way wait pattern.
    Table 3.8 summarizes some examples.
    Table 3.8: Some irregular 3-way waits
    Example Wait Acceptance
    ȷff ff 3 kinds–9 tiles
    - 3 kinds–9 tiles
    a -- 3 kinds–9 tiles
    Notice that the number of tiles to win on in each pattern is smaller
    than those for the regular 3-way side waits, although the kinds of tiles
    to win on are the same (either 1-4-7, 2-5-8, or 3-6-9). This is because
    we are already using some of the winning tiles within the hand.
    80 CHAPTER 3. RIICHI MAHJONG BASICS
    Notice also that not all the wait patterns qualify as side wait, so
    claiming pinfu is not always possible (similarly, claiming single wait
    is not always possible). For example, the first pattern in Table 3.8 is
    essentially a 3-way stretched single shape; none of the waits embed-
    ded in this shape qualifies as side wait. In the second pattern, if we
    win on , the wait must be interpreted as single wait; if we win on
    , the wait must be interpreted as side wait; and if we win on ,
    we adopt whichever interpretation that generates the higher score.
    In the third pattern, winning on allows us to claim single wait if
    doing so gives us a higher score.
    Complex waits
    When a set is combined with a floating tile nearby, we get some
    complex wait patterns with multiple waits. Table 3.9 summarizes a
    few examples of irregular waits that involve a set and a floating tile.
    Table 3.9: Some irregular waits (set and a floating tile)
    Example Combination Wait Acceptance
    single and edge 2 kinds–7 tiles
    single and closed 2 kinds–7 tiles
    single and side - 3 kinds–11 tiles
    When a set is combined with a protorun, pair, or a four-tile shape,
    we get even more complicated waits. Table 3.10 summarizes only a
    few representative examples.
    3.4. WAITS 81
    Table 3.10: Some irregular waits (set and a protorun, pair, or a four-tile shape)
    Example Wait Acceptance
    3 kinds–5 tiles
    3 kinds–5 tiles
    ”" " 3 kinds–6 tiles
    ȷff - 3 kinds–7 tiles
    - 3 kinds–9 tiles
    - 3 kinds–9 tiles
    ȷff 3 kinds–10 tiles
    3 kinds–11 tiles
    82 CHAPTER 3. RIICHI MAHJONG BASICS
    3.5 Glossary
    Simple tiles (tanyao hai) are tiles between 2 and 8.
    Terminal tiles (yaochu hai) are 1 and 9.
    Honor tiles (jihai) are non-number tiles (dragon tiles and wind
    tiles).
    Value tiles (fanpai / yakuhai) include dragon tiles, seat wind tiles,
    and prevailing wind tiles. We get one han for a set of value tiles.
    Valueless wind tiles (otakaze hai) are wind tiles that are neither
    a prevailing wind tile nor a seat wind tile.
    Run (chow / sequence; shuntsu) is a set of three consecutive num-
    ber tiles.
    Set (pung / triplet; kotsu) is a set of three identical tiles.
    Quad (kong; kantsu) is a set of four identical tiles.
    Protorun (taatsu) is a set of two tiles in the same suit that can be-
    come a run when one more tile is added.
    Pair (toitsu) is a set of two identical tiles.
    Ready (tenpai) is when a hand is ready to win.
    1-away (1-shanten) is when a hand can be ready with one more tile.
    Perfect 1-away is when a 1-away hand has two side-wait protoruns
    and two pairs.
    Tile acceptance (ukeire) refers to the kinds and the number of tiles
    a hand can accept.
    3.5. GLOSSARY 83
    Stretched single (nobetan) shape is a set of four consecutive num-
    ber tiles.
    Bulging float (nakabukure) shape is a four-tile shape that is made
    up with a run and one floating tile in the middle of the run.
    Skipping shape is a four-tile shape made up with a run and one
    floating tile located at two tiles away from the run.
    Chapter 4
    The five-block method
    In introducing basic building blocks of riichi mahjong in the pre-
    vious chapter, I have also touched upon a number of important tile
    efficiency principles — e.g., superiority of side-wait protoruns, the
    value of having two pairs in a hand rather than three, and the value
    of stretched single or bulging float shapes, to name a few.
    These principles are all important, but trying to take all of the
    important principles into consideration at once could be a daunting
    task. We have to make our discard choice in a limited amount of
    time,1 and tile efficiency is not the only factor we need to consider in
    making a discard choice. Moreover, some of the tile efficiency prin-
    ciples can at times clash with one another, requiring us to make a
    judgement call about which principle to follow. For example, we may
    at times wonder whether to retain a bulging float shape or to retain
    two pairs in a hand, when we have to discard one of the two.
    The five-block method I introduce in this chapter will help us
    prioritize between competing principles and find the most efficient
    discard choice quickly.2 The core idea of the five-block method is
    deceptively simple; we first identify five tile blocks in a hand — four
    groups + one head, or their candidates — and try to complete each
    block.
    1 Recall that, on regular (slower) tables on Tenhou, each discard choice must be
    made within 5 seconds. In offline games, we should make choices even faster
    so as not to irritate your fellow players.
    2 As I mentioned in the Preface, the exposition of this chapter is based on Makoto
    Fukuchi’s books. In particular, I am indebted to Makoto Fukuchi 2015 Haik-
    ouritsu Nyumon Doriru 76, Yousensha. ISBN978-4-8003-0634-0.
    4.1. FINDING A REDUNDANT TILE 85
    4.1 Finding a redundant tile
    We all understand that a standard hand must have five blocks of
    tiles — four groups and one head — to win. The five-block method
    encourages us to be always conscious about five tile blocks in a hand.
    Consider the following hand. What would you discard and why?
    ff %%%
    To figure out which tile is the least useful in this hand, let’s divide
    the hand into tile blocks, as follows.
    |{z} ff|{z} | {z } | {z } %%%| {z } (4.1)
    Notice that, although we do not know which block is going to be the
    head and which blocks are going to be four groups at the moment,
    the hand already has five tile blocks. This means that there is no need
    to increase or decrease the number of blocks from here.
    Looking at each of the five blocks, the pair of , the protorun
    ff, and the set of % are all self-sufficient; we keep them as they
    are. Our discard choice should thus be from the third or the fourth
    blocks, or . Let’s now compare these two closed-
    wait blocks. While is being useful within the block it belongs to,
    enabling the hand to accept , is completely redundant; the hand
    can accept without having . Therefore, the ideal discard here is
    .
    There are two key points to remember in applying the five-block
    method. First, we should not make any one of the five blocks “too
    86 CHAPTER 4. THE FIVE-BLOCK METHOD
    weak.”3 In the current example, if we discard , the block
    becomes an isolated closed-wait protorun, which is too weak com-
    pared with the other blocks. Likewise, if we discard , this block
    becomes a pair of . Since this hand already has two other pairs,
    having a third pair makes all the pairs in the hand too weak.
    Second, each of the five tile blocks should ideally have three tiles.
    In the current example, the block has exactly three tiles and
    so we should not choose a discard from this block. On the other hand,
    the block currently has four tiles so we should discard one
    from this block to make this a three-tile block.
    Five-block method
    Identify five tile blocks in a hand. Try to make sure:
    (1) there is no block that is too weak; and
    (2) each block has at most three tiles.
    3 Basically, any block that is weaker than a side-wait protorun is a weak block.
    4.1. FINDING A REDUNDANT TILE 87
    Let’s see another example.
    ff## #Dora
    We can easily see that there is one block in manzu (cracks), two blocks
    in pinzu (dots), and a pair of white dragons, giving us four blocks.
    This means that we need to have only one more block in souzu (bam-
    boos). Therefore, we divide the hand as follows.
    ff| {z } | {z } |{z} | {z } ##|{z} (4.2)
    Since we should not create a block that is too weak, discarding or
    ff is not an option. Notice that the block in souzu (bamboos) has
    four tiles. We should thus discard one from this block. In case the
    pair of white dragon later becomes a set, we should keep the pair
    of , leaving or as a discard candidate. Given that has a
    higher chance of creating a side-wait protorun, we should discard
    . Then, none of the five blocks is too weak, and each block has at
    most three tiles.
    In the two examples we saw above, you might have been able
    to identify the redundant tiles without really thinking too hard. If
    so, that was probably because you have implicitly and unconsciously
    applied the five-block method in your mind. The goal of this chapter
    is to train our mind further, so that it becomes our second nature to
    identify five tile blocks in a hand.
    88 CHAPTER 4. THE FIVE-BLOCK METHOD
    4.2 Alternative configurations
    Consider the following hand. What would you discard and why?
    ȷ %%%
    Let’s first divide the hand into five tile blocks.
    ȷ| {z } |{z} | {z } |{z} %%%| {z } (4.3)
    This makes it clearer that, just like the previous example, ȷ is
    creating a redundant closed-wait protorun, so we should discard it.
    Also, discarding ȷ makes this a three-tile block.
    However, there is an alternative way to divide this hand into five
    blocks, and situational changes may call for such an alternative con-
    figuration. Suppose that your opponents have already discarded all
    four tiles of . Suppose also that seems live in the wall. Or, sup-
    pose -ȷ tiles seem too dangerous to discard against an opponent.
    Then, we might want to divide the hand in the following way instead.
    |{z} ȷ|{z} | {z }
    2
    %%%| {z } (4.4)
    That is, we aim to make the pair of the head of this hand, and
    we seek to have two runs in pinzu (dots). If we discard , this block
    becomes . Recall that a block like this can be split into
    4.2. ALTERNATIVE CONFIGURATIONS 89
    + (recall the discussion of double closed shape in
    Section 3.3.1). Therefore, this block can accept as well as -
    to make two runs in pinzu. The block in pinzu will have six tiles, but
    this is OK because this block is worth two.
    To master the five-block method, we need to be able to instanta-
    neously envision the first block configuration (4.3) the moment we
    see this hand. However, that is not enough. We should also be able
    to imagine an alternative configuration (4.4) at the same time. In the
    game of mahjong, situations change very quickly each time a new
    tile gets drawn or a new tile gets discarded. Therefore, the ideal
    five-block configuration would also change accordingly as situations
    evolve. We thus need to develop our skills to picture many possi-
    ble five-block configurations and to prepare for possible situational
    changes that would call for a change in the configuration.
    I provide several exercises in the following pages. The answer
    key to each exercise is provided on the next page. Try not to look at
    the answers before you actually derive your own answer.
    Exercises: finding a redundant tile
    Exercise 1
    What would you discard?
    How do you divide the hand into tile blocks?
    ȷȷ aa Draw
    90 CHAPTER 4. THE FIVE-BLOCK METHOD
    Answer 1
    |{z} ȷȷ|{z} | {z } aa| {z }
    2
    With the draw of , we now have a 3-way side-wait block in
    souzu (bamboos). or a could be our back-up candidate for
    the head, in case we draw another ȷ. Since there is a potential
    for sanshoku (Mixed Triple Chow) of 345, we discard .
    Exercise 2
    What would you discard?
    How do you divide the hand into tile blocks?
    ff
    Draw
    4.2. ALTERNATIVE CONFIGURATIONS 91
    Answer 2
    ff|{z} | {z } | {z } |{z} | {z }
    Before we drew the third , the pinzu (dots) tiles were
  • + , so the was simply a floating tile. Now
    that we have another , the five-block configuration changes ac-
    cordingly. The ideal discard is , as this has become redundant.
    Exercise 3
    What would you discard?
    How do you divide the hand into tile blocks?
    ȷȷff a Draw
    92 CHAPTER 4. THE FIVE-BLOCK METHOD
    Answer 3
    | {z } ȷ ȷff| {z } |{z} |{z} a| {z }
    There are two “side wait plus one” shapes, and a,
    that might later become the head or a run. At this point, how-
    ever, we cannot determine which one will be which, so we should
    keep them as they are. One of the two ȷ has become an obvious
    redundancy so we should discard one.
    Exercise 4
    What would you discard?
    How do you divide the hand into tile blocks?
    ȷ" Draw
    4.2. ALTERNATIVE CONFIGURATIONS 93
    Answer 4
    ȷ| {z }
    2
    |{z} |{z} | {z } "
    The " is obviously redundant, but is also useless. Without
    , the hand can accept . Since honor tiles can be used as a
    safety tile (see Chapter 8), we discard first.
    Exercise 5
    What would you discard?
    How do you divide the hand into tile blocks?
    ffff a
    Draw Dora
    94 CHAPTER 4. THE FIVE-BLOCK METHOD
    Answer 5
    |{z} ffff| {z } | {z } |{z} a| {z }
    This is a bit difficult, as there are so many closed-wait protoruns.
    Recall that each tile block should have at most three tiles and that
    pairs are most valuable when there are two of them in a hand.
    The block in pinzu (dots) has four tiles, so we discard one from
    this block. Since is dora, we discard , leaving the double
    closed shape around dora: .
    Exercise 6
    What would you discard?
    How do you divide the hand into tile blocks?
    Draw
    4.2. ALTERNATIVE CONFIGURATIONS 95
    Answer 6
    | {z } | {z }
    2
    | {z }
    2
    Finding the best discard by actually comparing tile acceptance
    counts for each possible discard candidate is super tedious. The
    five-block method simplifies the process quite a bit. Since we
    have two blocks in pinzu (dots) and two blocks in souzu (bam-
    boos), we only need one block in manzu (cracks), hence one is
    redundant. If we discard , the hand can be made ready with
    11 kinds–34 tiles. If we discard or , the hand can be
    ready only with 6 kinds–19 tiles.
    Exercise 7
    What would you discard?
    ff a Draw
    96 CHAPTER 4. THE FIVE-BLOCK METHOD
    Answer 7
    |{z} ff | {z } | {z } a| {z }
    2
    Do not discard the just because it forms a closed wait or
    because discarding it gets us tanyao (All Simples). Avoiding
    closed wait too much and being hung up on tanyao are two
    pathologies common among intermediate players.
    The block in souzu (bamboos) is actually not too bad; this is a
    stretched single plus one, which can become either two runs im-
    mediately (if we draw ), one run plus one side-wait protorun
    (if we draw any of ), or one run plus the head (if we draw
    or a). Note also that we need both and , because this
    part may become the head if we get two runs in souzu (bam-
    boos); when we get the head in souzu (bamboos), we will treat
    this part as a side-wait protorun. We thus discard ff.
    4.3. SELECTING TILE BLOCKS 97
    4.3 Selecting tile blocks
    All the hands we have seen so far in this chapter already have
    five tile blocks. In practice, however, this is not always the case. A
    hand can sometimes have fewer or more tile blocks. Since we need
    to have exactly five blocks to win a hand, we will need to bump up
    tile blocks by using a floating tile when we have fewer of them or to
    discard some blocks entirely when we have a plethora of them.
    In selecting which tile blocks to keep and which ones to discard,
    we focus on a combination of the following three criteria:
  1. tile efficiency;
  2. hand value;
  3. the safety of tiles to be discarded.
    As we will see below, we can sometimes find a block to discard based
    on all the three criteria. Consider the following hand. How do we
    divide the hand into tile blocks, and what would you discard?
    Red
    a Draw
    We can see that the hand currently has six tile blocks, as follows.
    | {z } | {z } |{z} |{z} |{z} a|{z}
    Since the first two tile blocks are already complete and the third block
    is the head, our discard choice should be from the last three tile
    blocks, , , or a.
    98 CHAPTER 4. THE FIVE-BLOCK METHOD
    From a perspective of tile efficiency, discarding the block
    means that we lose the ability to accept both and . On the other
    hand, if we discard the a block, we only lose the ability to accept
    ; because of the block, we can still accept . We should thus
    choose between the two blocks in souzu (bamboos). Keeping the
    is desirable from a perspective of hand value (it is a red five) as
    well as safety (discarding a is much safer than discarding ,
    generally speaking). Therefore, the three criteria collectively suggest
    that we should discard a.
    In practice, however, satisfying all three criteria may not be fea-
    sible. A common tradeoff we face is between speed and hand value.
    That is, maximizing tile efficiency to gain speed often entails giving
    up possibilities of pursuing an expensive hand. Consider the follow-
    ing hand.
    ffff
    Let’s divide the hand into tile blocks. There are several ways to do
    this. One way to do this is to split it into the following blocks.
    | {z } ffff|{z} |{z} |{z} |{z} |{z}
    If we simply maximize tile efficiency, we discard , as we already
    have six tile blocks and we won’t need any more floating tile.
    However, as it stands, the hand has no yaku and it is likely to be
    a very cheap riichi-only hand. Moreover, the hand has three pairs,
    which is not ideal as we saw in the previous chapter. Therefore, we
    4.3. SELECTING TILE BLOCKS 99
    might want to split the hand into the following five blocks.
    ffff| {z } |{z} |{z} |{z} |{z}
    We count the floating as an independent block, hoping it to grow
    into a run. We also treat the tiles in manzu (cracks) as a single block,
    hoping to get at least one group or the head out of it. We thus discard
    one now, then another in the next turn. Depending on what
    tile gets drawn, our five-block configuration will be different.
    For example, suppose we draw and then . We will then have
    the following.
    ffff| {z } |{z} |{z} | {z } |{z}
    We will discard the as a first step toward reducing the number of
    tiles in the manzu (cracks) block to three. We can now see that this
    hand has a potential of getting sanshoku of 345 as well as pinfu and
    tanyao.
    On the other hand, if we draw ȷ and then , we can expect to
    have two groups in manzu (cracks) so we will discard .
    ȷffff| {z }
    2
    |{z} |{z} |{z}
    In selecting tile blocks, we should try to achieve the best balance
    between speed and hand value. Don’t fantasize too much about get-
    ting an expensive hand. At the same time, don’t fixate too much
    100 CHAPTER 4. THE FIVE-BLOCK METHOD
    about tile efficiency at the cost of hand value. This is, of course, easier
    said than done; it is quite difficult even for advanced players.
    Exercises: selecting tile blocks
    Exercise 8
    What would you discard?
    How do you divide the hand into tile blocks?
    ff Draw
    4.3. SELECTING TILE BLOCKS 101
    Answer 8
    | {z } ff|{z} |{z} |{z} |{z} | {z }
    The hand currently has six blocks so we need to get rid of one.
    The block is the weakest – it is the only closed-wait pro-
    torun – so we should get rid of this one. We should discard
    first; if we draw we will discard to leave the possibility of
    pinfu. If not, we discard next, and then .
    Exercise 9
    What would you discard?
    How do you divide the hand into tile blocks?
    a##
    Draw
    102 CHAPTER 4. THE FIVE-BLOCK METHOD
    Answer 9
    | {z } | {z }
    2
    |{z} a|{z} ##|{z}
    We were planning to discard the block because this was the
    weakest block among the six blocks in this hand. However, now
    that we drew another , the block is now the weakest. We
    thus discard .
    Exercise 10
    What would you discard?
    How do you divide the hand into tile blocks?
    ȷff a"" Draw
    4.3. SELECTING TILE BLOCKS 103
    Answer 10
    |{z} ȷff| {z } |{z} | {z } a|{z} “”|{z}
    The hand currently has six blocks so we need to get rid of one.
    Comparing the two closed-wait blocks and , the
    block is more valuable because it is adjacent to a run. If we draw
    , we will get a 3-way side-wait block. On the other hand, the
    block will only become a 2-way side-wait block when we
    draw . We should discard first, not , because if we draw
    next, we will discard the block.
    Exercise 11
    What would you discard?
    How do you divide the hand into tile blocks?
    ff a
    Draw
    104 CHAPTER 4. THE FIVE-BLOCK METHOD
    Answer 11
    ff|{z} | {z } |{z} |{z} a| {z }
    2
    Now that we have a 3-way side-wait block in souzu (bamboos),
    we should get rid of one block. Comparing a closed-wait block
    ff and two pairs and , we should value the closed-
    wait block. This is because the hand has three pairs already so we
    should get rid of one of them. Since we see a (remote) possibility
    of sanshoku of 567, we should discard .
    4.4 Building a block
    When a hand has fewer than five blocks, we need to build a new
    block, possibly from a floating tile we already have in the hand. In
Summary

doing so, we should envision the kind of yaku that the hand is going
to have eventually. Consider the following hand. Suppose you are
the dealer and this is East-1. What would you discard?
ȷffff a %"
As usual, we will split the hand into blocks. Notice that the hand
has at most four blocks only.
ȷffff| {z }
2
| {z } a| {z } % "
We should thus compare the four floating tiles % " in terms
4.4. BUILDING A BLOCK 105
of their relative capabilities to grow into an independent block. Of
these four tiles, is the strongest candidate, because it can form a
side-wait protorun with two kinds of tiles, and . Any simple tiles
between 3 and 7 are a strong floating tile because of their ability to
form a side-wait protorun. Terminals (1 and 9) will never become
a side-wait protorun, and 2 and 8 can become a side-wait protorun
when paired with only one kind of tiles (3 or 7). However, number
tiles are still stronger than honor tiles because honor tiles can never
form a run.
We should thus choose between the two honor tiles, % and ".
Which one should we discard? Notice that this hand is clearly a
pinfu hand and that it is currently lacking the head. Since value tiles
can never be the head of a pinfu hand, we should discard % rather
than ".
We may want to choose a discard from an existing block rather
than discarding a floating tile in order to enhance the hand value.
Consider the following hand.
ȷȷ a
From a pure perspective of tile efficiency, the discard choice should
be either a or , for discarding either of the three will maximize
tile acceptance. The block configuration behind such a decision is as
follows.
ȷ|{z} ȷ|{z} | {z } |{z} a| {z }
However, doing so makes it almost inevitable that the hand ends up
having a low score and/or a bad wait. Alternatively, we can expect
106 CHAPTER 4. THE FIVE-BLOCK METHOD
the stretched single shape a to produce two runs, to form
a run, and the tiles in manzu (cracks) to produce one run, as follows.
ȷȷ| {z } | {z } |{z} a| {z }
2
We should thus discard the for now, anticipating to discard the
pair of eventually. That way, we can expect to have tanyao, pinfu,
and possibly sanshoku.
Exercises: building a block
Exercise 12
What would you discard?
How do you divide the hand into tile blocks?
Red
a
4.4. BUILDING A BLOCK 107
Answer 12
| {z } |{z} | {z } | {z } a| {z }
If we were to simply maximize tile acceptance, the discard choice
should be either or . However, that would make the block
in manzu (cracks) too weak. Breaking the or is
not ideal, as these blocks are very strong. We should therefore
discard the to get rid of this edge-wait block. This will tem-
porarily reduce the number of blocks from five to four, but we
can expect to get back to five soon with this hand.
Exercise 13
What would you discard?
How do you divide the hand into tile blocks?
Red
a
108 CHAPTER 4. THE FIVE-BLOCK METHOD
Answer 13
|{z} |{z} | {z }
2
| {z } a| {z }
Discarding or will make this hand 1-Away, so our choice is
between these two options. Notice that the block is weaker
than the other four. As a back up, we should keep two to
maintain the bulging float block in pinzu (dots) for now, hoping
to get two runs out of it. If we draw - or - first, we will
get rid of the block. We should thus discard . If we draw
any of , we should do insta-riichi.
Exercise 14
What would you discard?
How do you divide the hand into tile blocks?
Red
a
4.4. BUILDING A BLOCK 109
Answer 14
| {z }
2
| {z } |{z} a| {z }
As we drew another , the block in manzu (cracks) is now a
decent shape. This can become one group and the head with a
draw of . Therefore, we should discard to break
the bulging float shape.
Chapter 5
Pursuing yaku
As we saw in the previous chapter, we often face a tradeoff be-
tween speed (tile efficiency) and hand value. In modern riichi mahjong,
the value of pursuing expensive yaku is much diminished because of
red fives. For example, ryanpeiko (Twice Pure Double Chow) is a
beautiful three-han yaku, but it is extremely difficult to make this
yaku. We can achieve the same hand value more easily with riichi +
dora + one red five. We thus tend to think of expensive yaku as some-
thing that emerges in a hand (almost) by chance, not something we
actively pursue. Given that we can get high scores also from ippatsu,
ura dora, and tsumo, getting the hand ready for riichi is generally
more important than pursuing expensive yaku.
That being said, always trying to maximize tile efficiency with-
out regard for yaku is not the best strategy, either. We should thus
design a five-block configuration with an eye to possible yaku we can
reasonably get. Moreover, sometimes situations call for an expensive
hand. For example, when you are ranked fourth in South-4, and the
player who is currently ranked third has 10000 more points than you
do, you should aim for mangan tsumo or haneman ron to improve the
placement (more on this in Chapter 10), which will require that your
hand has some yaku other than just riichi and dora.
In this chapter, I will discuss some tips to get the following five
set of yaku.
5.1 sanshoku (Mixed Triple Chow) 5.2 ittsu (Pure Straight)
5.3 pinfu (Pinfu) 5.4 honitsu (Half Flush)
5.5 toitoi (All Pungs) and chiitoitsu (Seven Pairs)
5.1. HOW TO GET SANSHOKU 111
5.1 How to get sanshoku
Sanshoku (Mixed Triple Chow) is an elusive yaku. Even when
we make our hand ready for sanshoku, we may lose it at the very last
minute. For example, suppose we manage to get the hand ready for
sanshoku of 345, and we have a side-wait protorun as the final
wait. We will get sanshoku only if we win the hand on ; if we win
on ȷ, we will lose sanshoku.
On the other hand, it is possible to have a confirmed sanshoku,
but doing so often entails a significant loss in tile efficiency. For ex-
ample, if our wait were a closed-wait protorun instead, sanshoku
is confirmed; but, a closed wait of is not very good. As long as
we seek to utilize side waits to maximize tile efficiency, sanshoku be-
comes difficult to achieve. I will discuss the following seven methods
to capture this elusive yaku.
5.1.1 Floating 5.1.2 Switching
5.1.3 Double closed shape 5.1.4 Stretched single
5.1.5 Lining pairs 5.1.6 Golden
5.1.7 Crashing a meld
112 CHAPTER 5. PURSUING YAKU
5.1.1 Floating
Sanshoku 1
ȷ a "
What would you discard?
in this hand is essentially a redundant floating tile from a pure
tile efficiency perspective; we do not need it to accept . However,
if we keep it and discard " instead, we can hope to get sanshoku of
345. The best case scenario is to draw first, after which we discard
ȷ.
That being said, keeping a floating tile this way is risky. What if
an opponent calls riichi after we discard "? We will have to discard
either or ȷ against the riichi’ed player when this hand becomes
ready. To make things worse, if we draw first, we will have to
discard the potentially dangerous (instead of ") with no benefit
of getting sanshoku.
Moreover, when we draw first, a difficult question arises. Con-
sider the following hand.
ȷ a Draw
Should we discard ȷ and have a closed-wait hand in hopes of getting
sanshoku, or should we discard and give up on sanshoku in pur-
suit of tile efficiency? If a hand has at least one dora or tanyao (All
Simples), we should discard to choose a side wait pinfu hand.
Only when there is no other yaku or dora in a pinfu hand, it is OK
to choose closed-wait sanshoku over side-wait pinfu.1
1 We will talk more about a tradeoff of this kind in Chapter 7.
5.1. HOW TO GET SANSHOKU 113
5.1.2 Switching
Sanshoku 2
ȷȷ Draw
What would you discard?
The hand already has five tile blocks and all the blocks are strong;
in fact, this is a perfect 1-away hand.2 It is thus OK to discard
we just drew. After all, that is the best discard from a tile efficiency
perspective.
However, if we need an expensive hand, we can keep and dis-
card instead. The resulting loss in tile efficiency is not very big,
as we would still have a strong 1-away hand with two side-wait pro-
toruns: and . In addition, serves as a floating tile to
approach sanshoku of 234. Keep in mind that we should give up on
sanshoku and do insta-riichi if we draw any of first (un-
less you absolutely need mangan or above to improve the placement
in South-4).
On the other hand, if we draw or first, the hand will be 1-
away from ready for sanshoku. For example, with a draw of , the
hand becomes the following.
ȷȷ Draw
We should discard and then to aim for sanshoku of 234. We
are switching from one protorun to another protorun to
approach sanshoku.
2 For the definition of perfect 1-away, see Section 3.2.7.
114 CHAPTER 5. PURSUING YAKU
The key here is that we are keeping the hand 1-away through-
out the entire process of switching from a perfect 1-away hand to a
sanshoku 1-away hand. You should not pursue sanshoku if switching
requires reverting a 1-away hand to 2-away.
5.1.3 Double closed (ryankan) shape
Sanshoku 3
ȷ a Draw
What would you discard?
As we have two blocks in manzu (cracks) and another two blocks
in pinzu (dots), we only need one block in souzu (bamboos). Our
choice is thus between (a) keeping a side-wait protorun to max-
imize tile efficiency and (b) keeping a double closed shape a
in hopes of getting sanshoku of 567.
If the hand has at least one dora or some yaku (such as tanyao),
we should give up sanshoku and discard a. Only if the hand has
no other yaku or dora, it is OK to discard to aim for sanshoku.
Keep in mind, though, that pursuing sanshoku with a hand like
this is risky, even compared with the floating method we discussed
in 5.1.1. We will end up with a bad-wait yaku-less hand if we draw
first. If we give up on sanshoku sooner and choose the side-wait
protorun , we can at least get pinfu.
5.1. HOW TO GET SANSHOKU 115
5.1.4 Stretched single (nobetan) shape
Sanshoku 4
ȷff a
Draw
What would you discard?
Notice that this hand has two possibilities of sanshoku, 567 or 678,
and we do not know at this point which one we can get. An excellent
way to aim for sanshoku with a hand like this is to discard to have
a stretched single shape ȷff that contains both 567 and 678.
If we draw any of first, we discard to aim for sanshoku of
567.
ȷff a
Draw
If we draw or first, we discard to aim for sanshoku of 678.
ȷff a
Draw
Either way, you get sanshoku without any loss of tile efficiency.
116 CHAPTER 5. PURSUING YAKU
5.1.5 Lining pairs
Sanshoku 5
a
Draw
What would you discard?
As we have one block in manzu (cracks) and two blocks in souzu
(bamboos), we need to have two blocks in pinzu (dots). More specif-
ically, we need the head and a group (preferably a run) in pinzu. We
therefore view the tiles in pinzu not as a collection of three pairs but
as a collection of one pair and two side-wait protoruns +
.
From a pure tile efficiency perspective, discarding and dis-
carding are equally good, and they are better than any other dis-
cards. However, there is a clear difference between the two from a
perspective of hand value. Suppose we discard first. If we then
draw , we will get the following hand.
a
Draw
Discarding makes this hand ready, but it is just a pinfu-only hand.
On the other hand, suppose we had discarded before drawing .
a
Draw
We can make this hand ready for pinfu and sanshoku of 456 by dis-
carding .
5.1. HOW TO GET SANSHOKU 117
Note that pre-committing to sanshoku of 456 by discarding
before drawing is massively inefficient. If we do that, the hand
becomes a very weak hand as follows.
a
This hand relies too much on the possibility of drawing first. If
we draw any of ȷ first, the hand will be a yaku-less and/or
bad-wait hand.
118 CHAPTER 5. PURSUING YAKU
5.1.6 Golden
Sanshoku 6
a
Draw
What would you discard?
If we keep and discard , the hand becomes what is known as
golden 1-away, as follows.
a
It is called “golden” because the hand is 1-away from ready for sanshoku
and 1-away from ready for ittsu (Pure Straight), two of the most
popular two-han yaku in riichi mahjong. Drawing or makes
the hand ready for ittsu, whereas drawing ff or makes the hand
ready for sanshoku of 789. The following are examples of golden 1-
away.
ff$$
ȷff
5.1. HOW TO GET SANSHOKU 119
5.1.7 Crashing a group
Sanshoku 7
ȷ Draw
What would you discard?
Notice that the hand can be made ready for pinfu if we discard .
However, that gives us a pinfu-only hand. If we need an expensive
hand, we could take a rather high-handed approach and crash an
already complete run by discarding . This might sound crazy, but
look how good a 1-away hand it becomes.
ȷ
If we draw or , the hand becomes ready for tanyao + pinfu +
sanshoku + iipeiko (Pure Double Chow). Drawing a also gets us
tanyao + pinfu + sanshoku, and drawing any of gets
us at least tanyao + pinfu, and possibly iipeiko as well.
120 CHAPTER 5. PURSUING YAKU
5.2 How to get ittsu
Ittsu (Pure Straight) is another popular two-han yaku. As we
will see below, even when ittsu appears to be a possibility, it is not al-
ways worthwhile to pursue this yaku at the cost of tile efficiency. We
will see several instances where pursuing ittsu is and is not worth
the cost.
5.2.1 Two non-overlapping runs
The key to getting ittsu is to pay attention to two non-overlapping
runs in a given suit. For example, suppose a hand has two non-
overlapping runs such as the following.
+ȷff
+
+a
Then, as soon as we draw another non-overlapping tile in the same
suit, ittsu is almost around the corner. Consider the following hand.
Ittsu 1
ȷff Draw
What would you discard?
From a pure tile efficiency perspective, the best discard choice is .
However, doing so means giving up on ittsu and poking our way
toward a bad-wait yaku-less hand. That is not a very good path to
take even if we are ahead of the game in South-4 and don’t need an
expensive hand.3
3 We would still want to have at least one yaku in a hand so that we can win it
5.2. HOW TO GET ITTSU 121
We should rather treat as a treasure; we now have a realis-
tic possibility of getting ittsu. Let’s apply the five-block method to
figure out an alternative discard.
| {z } ȷ|{z} ff|{z} | {z } | {z }
We are hoping to get three blocks in manzu (cracks) to have ittsu,
so we need one block in pinzu (dots) and another block in souzu
(bamboos). Recall the principle that each block should have at most
three tiles, which suggests we discard one tile from the block in souzu
(bamboos). The choice now boils down to discarding or . Re-
call also that the value of pairs is maximized when there are two pairs
in a hand. We should thus discard .
5.2.2 Six-tile block with intervals
Consider different six-tile configurations where we have a chunk
of six tiles with a few intervals among them. For example, consider
the following six-tile blocks.
+ȷ+ff
++
++a
We do see ittsu on the horizon with each of these tile chunks, but
aiming for ittsu with these blocks is not very realistic. Take the first
six-tile block in manzu (cracks), for example. Even when we draw ,
we would want to discard to have a double closed shape ȷ
without calling riichi.
122 CHAPTER 5. PURSUING YAKU
and a run ff rather than trying too hard to pursue ittsu. With
this in mind, consider the following hand.
Ittsu 2
a Draw
What would you discard?
Although we see a remote possibility of ittsu in souzu (bamboos),
pursuing it requires we fill in three closed-wait protoruns in souzu:
, , and a .
It would be more practical to discard and then ; we would
consider the tile blocks in souzu as a collection of two side-wait pro-
toruns: and a + two redundant terminal tiles: , rather
than considering it as a collection of three closed-wait protoruns.
5.2.3 Run + side-wait protorun
At one step prior to getting two non-overlapping runs, we may
have one run and a non-overlapping side-wait protorun in a given
suit. The following blocks are examples of such run + side-wait pro-
torun combinations.
+ff
+
+a
When we have a combination like these, a draw of or (left ex-
ample), or (middle example), or (right example) gener-
ates a realistic probability of getting ittsu. Below are the resulting
5.2. HOW TO GET ITTSU 123
tile blocks in each instance. You can pursue ittsu with any of these
blocks.
+ +ff + + ++a
+ +ff ++ ++a
However, if the protorun is instead a closed-wait or an edge-wait
one, the chance of getting ittsu is much diminished. The follow-
ing blocks are examples of such run + closed- or edge-wait protorun
combinations. You may not want to pursue ittsu with these blocks.
+
+
+a
If the run becomes a bulging float block, you may want to give up on
ittsu and discard the closed- or edge-wait protorun part. With this
in mind, consider the following 2-away hand.
Ittsu 3
## Draw
What would you discard?
Now that we drew a tile that creates a bulging float block in manzu
(cracks), it is about time to give up on ittsu. Discarding allows
124 CHAPTER 5. PURSUING YAKU
the hand to accept 9 kinds–25 tiles; if we stick with ittsu and discard
, the hand can accept only 4 kinds–10 tiles.
Moreover, although the hand is 2-away from ready, it is 3-away
from ittsu. Pursuing ittsu with a hand like this is not very practi-
cal.
5.2.4 Ittsu vs. side wait
As we saw with sanshoku hands, we often face a choice between
pursuing yaku and keeping a side-wait protorun. Consider the fol-
lowing 1-away hand.
Ittsu 4
ȷff
Draw Dora
What would you discard?
If we discard we drew, the hand is a perfect 1-away hand; the final
wait can always be side wait. On the other hand, if we discard ,
we have a confirmed ittsu hand. Which option should we choose?
If we compare tile acceptance counts for the two scenarios, the
option of confirming side wait is slightly better (6 kinds–18 tiles vs.
5 kinds–16 tiles). However, doing so means we give up on ittsu.
Moreover, giving up on ittsu means that we can never call pon or
chii with this hand because there is no yaku in the hand. On the
other hand, the second option allows us to call pon on or call
chii on . Even though the kinds and the number of acceptable
tiles are smaller, the second option would be more efficient if we take
melding into account.
5.3. HOW TO GET PINFU 125
5.3 How to get pinfu
Although pinfu is only worth one han, the requirements to claim
pinfu are rather demanding. The key to getting pinfu is to build
side-wait protoruns even at the cost of tile efficiency. Consider the
following hand.
Pinfu 1
Draw
What would you discard?
We already have five tile blocks in this hand. From a pure tile effi-
ciency perspective, discarding one of the two floating tiles or
is the best. However, doing so significantly reduces our chance of
getting pinfu. If we aim for pinfu we should discard the edge-wait
protorun and keep the two floating tiles, which we hope may
grow into a side-wait protorun.
Suppose we discarded , then we drew , after which we dis-
carded . Now the hand is 1-away again, this time with two side-
wait protoruns. Suppose further that we drew !.
Pinfu 2
!Draw
What would you discard?
We should keep ! as a safe tile and discard . It is true that keeping
has an advantage; if we draw , we will get a 3-way side-wait
block in souzu (bamboos). Even a draw of a improves this hand
slightly. This is because having and is not very efficient
due to the overlap of the waiting tiles; both blocks wait for . It
126 CHAPTER 5. PURSUING YAKU
would be better to have a and , rather than having
and .
However, keeping comes at a cost. Even when we draw ,
we will then have to discard or , possibly against an op-
ponent’s riichi. Therefore, once we get a 1-away with two side-wait
protoruns (side & side 1-away; ryanmen-ryanmen 1-shanten), we
should try to keep a safety tile in the hand.
Even when we draw a tile that makes a hand perfect 1-away, we
may still want to have a safety tile. For example, drawing any of
makes the hand above perfect 1-away. Although perfect
1-away is better than side & side 1-away in terms of tile acceptance, a
perfect 1-away hand can end up not having pinfu because a set can
emerge in the hand.
There is one exception to this, however. If the floating tile leaves
a possibility of enhancing the hand value by at least three han, it is
OK to keep it instead of a safety tile. Consider the following hand.
Pinfu 3
ff !
Draw Dora
What would you discard?
Keeping ! is safer, but keeping leaves the possibilities of getting
ittsu and having dora, possibly at the same time. In this case, we
would rather discard !.
5.3. HOW TO GET PINFU 127
Building the head
To claim pinfu, the head must be a pair of number tiles or val-
ueless wind tiles. Therefore, try not to discard terminals or valueless
wind tiles lightly when having a pinfu hand. Keep this in mind espe-
cially when a hand is lacking any pair. Assuming you are the South
player in the 1st turn in East-1, consider the following hand.
Pinfu 4
ȷ a!$
What would you discard?
The hand has a potential to have pinfu, so we should not discard any
of ! at this point. All of these three tiles may appear useless,
but they can be the head of a pinfu hand when any of them grows
into a pair. On the other hand, the value tile $ cannot be the head
of pinfu. We should discard $ in this case.
128 CHAPTER 5. PURSUING YAKU
5.4 How to get honitsu
Going for honitsu (Half Flush) can be a good way to achieve high
hand values. As we can combine honitsu with many other yaku,
including fanpai, toitoi, chanta (Outside Hand), ittsu, among
others,4 we can aim for mangan relatively easily. The fact that honitsu
is worth two han even when we open our hand means we can also
enhance the speed by melding without making our hand too cheap.
5.4.1 Conditions to go for honitsu
When judging whether to go for honitsu or not, we should con-
sider two factors — five-block potential and hand values with and
without honitsu.

  1. Five-block potential
    The most important factor to consider is whether or not your hand
    has five tile blocks or block candidates (i.e., floating tiles) necessary
    for honitsu. Assuming you are the South player in the 6th turn in
    East-1, consider the following hand.
    Honitsu 1
    fffflffl!%%
    Would you go for honitsu?
    In order to figure out if it is practical to pursue honitsu with this
    hand, let’s apply the five-block method.
    |{z} ff|{z} fflffl|{z} %%|{z} !|{z}
    4 Technically speaking, honitsu can be combined with chiitoitsu, shousangen
    (Little Three Dragons), honroutou (All Terminals and Honors), pinfu,
    iipeiko, ryanpeiko, san ankou (Three Concealed Pungs), and san kantsu
    (Three Kongs) as well.
    5.4. HOW TO GET HONITSU 129
    We can count on the two pairs of fanpai, fflffl and %%, to be two
    tile blocks, a pair of and a protorun ff to be another two
    blocks, yielding four blocks in total. In addition, we can reasonably
    expect either of the two floating tiles ! to produce the fifth block.
    Therefore, you can go for honitsu with this hand.
    In addition, the tiles that are made redundant in the hand if we
    choose honitsu are an isolated and a closed-wait protorun .
    Keeping these tiles would not make this hand particularly more effi-
    cient anyway, so we can go for honitsu without much hesitation.
    Even when we have a side-wait protorun or a pair to discard, we
    may still want to go for honitsu. For example, with the following
    two hands, you should go for honitsu even though doing so means
    you have to discard a side-wait protorun or a pair.
    !###
    ffl "%
  2. Hand value
    Another factor to consider is hand value comparison with and
    without honitsu. If your hand does not have any yaku potential (e.g.,
    pair or set of fanpai) other than honitsu, you may end up getting
    a honitsu-only hand, which is very cheap (2000 or 2600 points). In
    such situations, you should not aim for honitsu; you should try to
    make the hand ready without melding and go for riichi. Assuming
    you are the South player in East-1, consider the following hand.
    130 CHAPTER 5. PURSUING YAKU
    Honitsu 2
    ȷaa!!""
    Would you go for honitsu?
    Since West and North are both valueless wind tiles, this hand is likely
    to become honitsu-only if you decide to go for honitsu. Although
    this hand has five tile blocks necessary for honitsu, you should not
    go for honitsu.
    At the same time, when the hand value is sufficiently high (
  1. without honitsu, you should not go for honitsu at the cost of
    tile efficiency. Assuming you are the South player in East-1, consider
    the following hand.
    Honitsu 3
    Red
    ff $$$! H
    What would you discard?
    This hand is worth 5200 points without honitsu (Seat Wind + Green
    Dragon + red five), so you should discard ff to maintain a side &
    side 1-away status. If were not your seat wind, you should go for
    honitsu.
    5.4. HOW TO GET HONITSU 131
    5.4.2 Discard
    When pursuing honitsu, pay attention to the order of your dis-
    cards. Consider the following hand. You called pon on # just now,
    deciding what to discard.
    Honitsu 4
    ȷ""% ##K
    What would you discard?
    You should pursue honitsu, so are your discard candidates.
    You will discard all three of them eventually, but you should discard
    them in a way that looks less obvious that you are collecting tiles in
    manzu (cracks). If you discard first then next, the opponents
    might (correctly) guess that you are doing honitsu with manzu tiles.
    In particular, the Left player may stop discarding tiles in manzu that
    you could call chii on. You should thus discard first then
    next, so that the opponents cannot know if you are collecting manzu
    or pinzu (dots). They will eventually find out that you are collecting
    manzu, but you should delay that as much as possible.
    132 CHAPTER 5. PURSUING YAKU
    5.4.3 Melding
    When you start melding with a honitsu hand, try to leave the
    possibility of achieving the maximum hand value. Assuming you
    are the South player in the 6th turn in East-1, consider the following
    hand.
    Honitsu 5
    !""$$
    Which tile would you call?
    With this hand, do not start melding with a chii of or a pon of
    " if you are playing without red fives; you may end up with a very
    cheap (2000 points) honitsu-only hand. Suppose you managed to
    call pon on $, resulting in the following hand.
    !"" $L$
    Calling chii on or pon on " is still not ideal. The only melding
    you should do is to call chii on to have the following hand.
    !"" 3 $L$
    Notice that the two floating tiles ! allow us to envision two
    possibilities of getting a 7700 hand. On the one hand, if you draw
    ! or call pon on “, you get honitsu + Green Dragon + chanta
    (Outside Hand), as follows.
    !!”" 3 $L$
    5.4. HOW TO GET HONITSU 133
    ! ““J 3 $L$
    On the other hand, if you draw or , the hand will be ready
    for honitsu + Green Dragon + ittsu.
    ”” 3 $L$
    "" 3 $L$
    134 CHAPTER 5. PURSUING YAKU
    5.5 How to get toitoi / chiitoitsu
    5.5.1 Toitoi vs. chiitoitsu
    When pursuing chiitoitsu (Seven Pairs), you may find your-
    self standing at a crossroad between chiitoitsu and toitoi (All
    Pungs). Specifically, what should we do when one of the pairs in
    a 1-away chiitoitsu hand becomes a set? Assuming you are the
    South player in the 6th turn in East-1, consider the following hand.
    Toitoi vs. chiitoitsu
    ffff a$$" Draw
    What would you discard?
    If we discard that we drew, the hand is 1-away from ready for
    chiitoitsu, accepting a" (3 kinds–9 tiles). On the other hand,
    if we keep it and discard a instead, the hand is still a 1-away chiitoitsu
    hand, albeit with smaller tile acceptance. However, doing so makes
    the hand also 2-away from ready for toitoi and possibly su anko
    (Four Concealed Pungs).
    Judgement criteria for a choice of this kind are summarized as fol-
    lows.
    Toitoi vs. chiitoitsu
    Choose chiitoitsu in the following situations.
  1. There is a futile pair in your hand.
  2. There is no pair of value tiles in your hand.
  3. There are three or more pairs of simple tiles between 3 and
    7 in your hand.
    5.5. HOW TO GET TOITOI / CHIITOITSU 135
    The first condition is by far the most important one. With the current
    hand example, if the opponents have already discarded two tiles of
    ff, the pair of ff in the hand is a futile pair (dead pair) that will
    never become a set. If there is one or more futile pair in your hand,
    you must stick with chiitoitsu. If not, you can go for toitoi.
    In addition, you may also want to take into account the second
    and the third conditions. Specifically, without having a pair of value
    tiles (fanpai), you may end up with a toitoi-only hand (2600 or
    even 2000 points). With one pair of value tiles, you can aim for 5200
    with toitoi; with two pairs of them, you can aim for mangan.
    The third factor to consider is whether there are not three or more
    pairs of simple tiles between 3 and 7. Consider the following hand.
    ȷffff##$%
    Suppose you start melding by calling pon on #,5 then get another
    pon on , resulting in the following hand.
    ffff% * #K#
    Since the remaining three pairs are all simple tiles between 3 and 7,
    the hand advancement often stops here. Because of their high versa-
    tility, simple tiles between 3 and 7 are very likely to be used by the
    opponents.
    5 Calling pon on # makes this 1-away chiitoitsu hand 2-away from ready for
    toitoi. Doing so would be acceptable if the remaining pairs were not simple
    tiles between 3 and 7.
    136 CHAPTER 5. PURSUING YAKU
    5.5.2 Standard hand vs. chiitoitsu
    Another kind of crossroad is between chiitoitsu and standard
    hand. Assuming you are the South player in the 6th turn in East-1,
    consider the following hand.
    Pinfu vs. chiitoitsu
    ȷȷa""
    Draw
    What would you discard?
    As we draw , we now have five pairs in the hand, making it 1-away
    from ready for chiitoitsu. However, the hand is also 2-away from
    ready if we interpret this hand as a standard hand.
    When a hand has this many side-wait protoruns, it makes more
    sense to view it as a standard hand rather than as a chiitoitsu hand.
    To figure out what tile to discard, let’s apply the five-block method.
    ȷȷ| {z }
    2
    |{z} |{z} a| {z } “”
    Since we already have five tile blocks in simple tiles, the pair of " is
    redundant. Discarding " means we are giving up on chiitoitsu,
    but we are maximizing tile acceptance to make the hand ready for
    tanyao as soon as possible. Doing so leaves a decent chance of getting
    pinfu and iipeiko as well. The expected hand value will actually be
    higher if we give up on chiitoitsu.
    On the other hand, when a hand has few side-wait protoruns but
    has several pairs, you should pursue a pair-based (set-based) hand
    5.5. HOW TO GET TOITOI / CHIITOITSU 137
    rather than a run-based hand. Assuming you are the South player in
    the 6th turn in East-1, consider the following hand.
    Run-based hand vs. set-based hand
    ffl # #
    Draw
    What would you discard?
    Although the hand has one side-wait protorun, we would not be very
    happy if it were to evolve into a complete run; we may end up with a
    very cheap hand with a bad wait. Alternatively, you should pursue
    chiitoitsu or toitoi with a hand like this. Let’s apply the five-block
    method to figure out what tile to discard.
    |{z} |{z} |{z} ##|{z} ffl
    Since we intend to build four blocks using the four pairs in the hand,
    we only need one more block from the rest of the tiles: ffl .
    Of these six tiles, ffl are clearly more valuable than others be-
    cause of their low versatilities. On the other hand, are less
    useful for you because these tiles have high versatility for the op-
    ponents. We should discard or first, keeping just in case
    we draw a red (in which case the hand is 1-away from ready for
    chiitoitsu).
    Part III
    Strategy Principles
    138

Chapter 6
Scoring
The scoring system in mahjong is quite complex. Getting profi-
ciency in score calculation requires a lot of practice. The good news
is that scoring is automatically done once you win a hand when you
play online. Even when you play offline, you can usually count on
your fellow players to help you get the correct score once you win a
hand.
However, you often need to calculate the (potential) scores of
your hand before you win the hand. This is because a lot of impor-
tant judgements you make during the game — riichi judgement, de-
fense judgement, and melding judgement, among others — depend
on the potential scores of your hand. Therefore, developing ability
to calculate the scores correctly and quickly without any help of oth-
ers is of utmost importance. I introduce some efficient methods of
score calculation in this chapter before we discuss riichi, defense, and
melding judgements in the subsequent chapters.
6.1 Three steps in score calculation
Every rule book of mahjong has comprehensive scoring tables
(similar to Tables 6.10 and 6.11 at the end of this chapter) that show
all possible scores for all possible minipoints (fu). Although such
tables are a good reference to have, it is not very efficient to try to
memorize everything in such tables.
A more practical approach would be to focus on a small number
of frequently observed patterns of scoring and memorize them cor-
rectly, while ignoring other, less important ones. Before introducing
6.1. THREE STEPS IN SCORE CALCULATION 141
some shortcuts to do efficient scoring, let’s first review the three re-
quired steps in score calculation, summarized in a box on the next
page.
Three steps in score calculation
Step 1: Count the number of han.
First, you need to figure out how many han a hand has. If
a hand has five or more han, skip Step 2 and go directly to
Step 3. If not, proceed to Step 2.
Step 2: Figure out the minipoints.
When a hand has four or less han, you then need to know
the hand’s minipoints. This does not mean, however, that
you always need to do some maths to get the correct mini-
points. We will discuss some practical shortcuts below.
Step 3: Get the score.
Based on the number of han (and possibly minipoints), you
get the score. You will have to memorize some score pat-
terns.
In the remainder of this chapter, I will first introduce basic meth-
ods of score calculation in Section 6.2. The basic methods involve
using some shortcuts in Step 2 above. Once you master the basic
methods, you will be able to calculate scores correctly most of the
time.1 When you master the contents of Section 6.2, you may skip
Section 6.3 and proceed to the next chapter. Section 6.3 covers more
advanced methods of score calculation, which would be necessary
1 In my impression, roughly 75 % of the hands we encounter can be covered by
the basic methods.
142 CHAPTER 6. SCORING
only in exceptional cases. This involves an exact calculation of mini-
points in Step 2 above.
6.2 Basic scoring

  1. Counting the number of han
    Step 1 in score calculation is counting the number of han in a
    hand. This is the most important part in score calculation, and there
    is no useful shortcut here. You need to be able to identify all the yaku
    in a hand as well as the associated han counts for each.
    A good way to practice this is to try to beat the automatic score
    counting on Tenhou. Whenever someone wins a hand, Tenhou dis-
    plays all the yaku and the associated han counts one after another in
    a few seconds. Try to identify all the yaku of your opponent’s hand
    before they get displayed automatically.
    Scores for limit hands
    When a hand has five or more han, the hand is a limit hand.
    Scores of limit hands do not depend on minipoints so we can go di-
    rectly to Step 3. To get the score for a given han count, we utilize Table
    6.1. This is something you need to memorize.
    As you can see, there are some regularities and redundancies that
    make it relatively easy to memorize this table. The most important
    score of all is 8000 (mangan ron for non-dealer). This is the basis of
    all the other scores in this table. For example, haneman scores are
    1.5 times mangan scores, baiman scores are two times mangan scores,
    sanbaiman scores are three times mangan scores,2 and yakuman scores
    are four times mangan scores. In addition, scores for dealer are exactly
    2 Since bai means “twice” or “double” in Japanese, baiman literally means dou-
    ble mangan in Japanese. Similarly, sanbai means “triple,” so sanbaiman literally
    means triple mangan.
    6.2. BASIC SCORING 143
    Table 6.1: Scores for limit hands
    Han Name Ron Tsumo
    Non-dealer Dealer Non-dealer Dealer
    5 mangan 8000 12000 2000-4000 4000-all
    6–7 haneman 12000 18000 3000-6000 6000-all
    8–10 baiman 16000 24000 4000-8000 8000-all
    11–12 sanbaiman 24000 36000 6000-12000 12000-all
    13+∗ yakuman 32000 48000 8000-16000 16000-all
    ∗ A hand with 13+ han is scored as a sanbaiman with the revised EMA rules.
    1.5 times the corresponding scores for non-dealer in all limit hands.
    Finally, scores for tsumo (self draw) cases are simple and straight-
    forward; the dealer pays one half of the total, and each of the two
    non-dealers pays one fourth of the total. For example, in the case of
    mangan tsumo (8000), the dealer pays 4000 and non-dealers pay 2000
    each.
  2. Figuring out the minipoints
    When a hand has four or less han, you have to know the mini-
    points. As I pointed out earlier, this does not mean that you always
    have to count all the minipoint contributions from all the melds and
    wait in a hand. Such a calculation is required only in special cases.
    Instead, you can use the chart in Figure 6.1 that summarizes the six
    most frequently observed patterns you need to memorize.
    You can use this Figure as a flowchart. You first check if the hand
    is a chiitoitsu (Seven Pairs) hand. If it is, it is always 25 minipoints.
    If it is not, you then check if the hand has one or more quads (kongs).
    If it does, the hand is out of the scope of the basic methods. Ask for
    help from more experienced players after winning the hand. Ad-
    vanced methods we discuss in Section 6.3 will cover this exceptional
    144 CHAPTER 6. SCORING
    Shortcut for minipoint calculation
  3. chiitoitsu ) always 25 minipoints
  4. A hand has one or more quads ) Don’t bother.
  5. toitoi ) almost always 40 minipoints
  6. Pinfu
    • ron ) always 30 minipoints
    • tsumo ) always 20 minipoints
  7. Closed hand without pinfu
    • ron ) almost always 40 minipoints
    • tsumo ) almost always 30 minipoints
  8. Open hand ) almost always 30 minipoints
    Figure 6.1: Six most observed patterns
    case. Third, you check if the hand is toitoi (All Pungs).3 If it is, it’s
    almost always 40 minipoints unless it is a tanyao toitoi hand that
    is likely to have 30 minipoints.
    Once you rule out the first three cases (chiitoitsu, quads, and
    toitoi), the last three are the most important ones; the great major-
    ity of hands you see will be one of these three. Here, you check two
    things. First, check if it is a pinfu hand. If it is, it’s always 30 mini-
    points (ron) or 20 minipoints (tsumo). If it is not pinfu, you then
    check if it is a closed hand or an open hand. If it is a closed hand, it
    3 Note that we are only talking about open toitoi here. A closed toitoi does
    not require a minipoint calculation under any circumstance. If you win it by
    tsumo, it’s yakuman (su anko; Four Concealed Pungs); if you win it by ron, it’s
    at least mangan (toitoi and san anko).
    6.2. BASIC SCORING 145
    is almost always 40 minipoints (ron) or 30 minipoints (tsumo). If it
    is an open hand, it is almost always 30 minipoints whether you win
    it by ron or tsumo.
    Because of the importance of the cases 4, 5, and 6 (pinfu, closed,
    and open hand), we will first discuss these three cases. We will then
    discuss cases 1 and 3 (chiitoitsu and toitoi), which are way more
    exceptional.
    What do we mean by “almost always”?
    Before getting to score calculation, let me explain what we mean
    when we say something is almost always X minipoints in cases 5 and
    6 in Figure 6.1. With a non-toitoi hand without quads, check if the
    hand has one or more concealed set of terminal/honor tiles or its
    equivalent. Recall that one concealed set of terminal/honor tiles is
    equivalent to two open sets of terminal/honor tiles or two concealed
    sets of simple tiles in minipoints. Therefore, what we check is whether
    a hand has any of the following:
    • at least one concealed set of terminal/honor tiles;
    • at least two open sets of terminal/honor tiles;
    • one open set of terminal/honor tiles and one concealed set of
    simples;
    • at least two concealed sets of simples.
    When none of the four above exists in a non-toitoi hand without
    quads, a hand is always 40 minipoints if closed and always 30 mini-
    points if open. Therefore, there is really no need of an actual calcu-
    lation of minipoints with hands like the following.
    a %M%
    146 CHAPTER 6. SCORING
    Gfflffl ?
    ffa
    With these hands, we can simply check if it is a closed hand or not to
    determine if each hand has 40 minipoints (closed) or 30 minipoints
    (open).
    In addition, so-called “open pinfu” hands such as below 4 are
    always 30 minipoints. This is one of the two exceptions to minipoint
    calculation. For minipoint calculation, see Section 6.3.
    a ?
    On the other hand, if a hand satisfies any of the four conditions
    above, we need to calculate the minipoints by actually counting and
    summing all the minipoint contributions from all the melds, the head,
    and the wait to determine the minipoints of a hand. We will discuss
    this in Section 6.3.
  9. Getting the scores
    As Figure 6.1 makes clear, the case of 30 minipoints is the most
    important pattern. We thus start with this pattern. We will then
    proceed to the cases of 40, 20, and 25 minipoints.
    30 minipoints
    You get 30 minipoints when you get:
    4 Of course, one cannot claim pinfu with an open hand. What we mean by “open
    pinfu” here is that the hand shape satisfies the conditions for pinfu.
    6.2. BASIC SCORING 147
    • pinfu ron (always);
    • closed hand tsumo (almost always); or
    • open hand ron / tsumo (almost always).
    Scores for 30 minipoints are summarized in Table 6.2.
    Table 6.2: Scores for 30 minipoints
    Han Ron Tsumo
    Non-dealer Dealer Non-dealer Dealer
    1 1000 1500 300-500 500-all
    2 2000 2900 500-1000 1000-all
    3 3900 5800 1000-2000 2000-all
    4 7700 11600 2000-3900 3900-all
    5+ limit hand
    Compared with the limit hands table (Table 6.1), the regularities
    in the 30 minipoints table are less precise. For example, scores for
    dealer are only roughly 1.5 times those for non-dealer; tsumo scores
    are sometimes slightly bigger than the corresponding ron scores. For
    example, one-han tsumo (300-500) gives you 300 + 300 + 500 = 1100,
    which is slightly bigger than one-han ron (1000).
    Therefore, it would be more efficient if we just memorize these
    patterns as they are, rather than trying to simplify them. Japanese
    players tend to memorize Table 6.2 column-wise, as follows:
    148 CHAPTER 6. SCORING
    Scores for 30 minipoints
    • ron (non-dealer): 10, 20, 39, 77
    • ron (dealer): 15, 29, 58, 116
    • tsumo (non-dealer): 3-5, 5-10, 10-20, 20-39
    The benefit of memorizing this score table column-wise is that scores
    get (roughly) twice as big for an additional han. Moreover, if we
    memorize the tsumo scores for non-dealer, we can easily derive those
    for dealer. When I was trying to memorize these, I used to recite these
    sequences a number of times so that they get beaten into my head.
    40 minipoints
    You get 40 minipoints when you get:
    • non-pinfu closed hand ron (almost always); or
    • toitoi ron / tsumo (almost always).
    Scores for 40 minipoints are summarized in Table 6.3.
    Table 6.3: Scores for 40 minipoints
    Han Ron Tsumo
    Non-dealer Dealer Non-dealer Dealer
    1 1300 2000 400-700 700-all
    2 2600 3900 700-1300 1300-all
    3 5200 7700 1300-2600 2600-all
    4+ limit hand
    Just like we did with scores for 30 minipoints, I recommend you
    memorize this column-wise.
    6.2. BASIC SCORING 149
    Scores for 40 minipoints
    • ron (non-dealer): 13, 26, 52, mangan
    • ron (dealer): 20, 39, 77, mangan
    • tsumo (non-dealer): 4-7, 7-13, 13-26, mangan
    The good news is that the ron score sequence for non-dealer —13,
    26, 52— is a geometric progression; 13 2 = 26, and 26 2 = 52.
    Also, the ron scores for dealer —20, 39, 77— should look familiar to
    you if you have already memorized the 30 minipoints ron scores for
    non-dealer —10, 20, 39, 77.
    20 minipoints (pinfu tsumo)
    Scores for 20 minipoints are summarized in Table 6.4. This table is
    special in the sense that it does not have the ron score component
    nor the one-han row. This is because you get 20 minipoints only
    when you get pinfu + tsumo (hence we have at least two han). Even
    though this is a special case, pinfu + tsumo is far from a rare occur-
    rence. It is thus important to know how to get the correct scores for
    this case.
    Table 6.4: Scores for 20 minipoints
    Han Tsumo
    Non-dealer Dealer
    2 400-700 700-all
    3 700-1300 1300-all
    4 1300-2600 2600-all
    5+ limit hand
    Notice that there is an interesting similarity between the 20 mini-
    150 CHAPTER 6. SCORING
    points table (Table 6.4) and the 40 minipoints table (Table 6.3). The
    scoring patterns are almost identical, except that the required num-
    ber of han to get a certain score is one han smaller for 40 minipoints
    than for 20 minipoints; that is, to get 400-700, we need 2 han with 20
    minipoints, whereas we only need 1 han with 40 minipoints.
    This is not a coincidence. In general, when we double the mini-
    points, we need one less han to get the same score. For example, a
    3 han–30 minipoints hand and a 2 han–60 minipoints hand have the
    same score (3900 for non-dealer; 5800 for dealer); a 2 han–25 mini-
    points hand and a 1 han–50 minipoints hand have the same score
    (1600 for non-dealer; 2400 for dealer). Therefore, once you memo-
    rize scores for 30 minipoints, we can easily deduce scores for hands
    with 60 minipoints. Similarly, we can deduce scores for hands with
    50 or 80 minipoints once we memorize scores for 25 or 40 minipoints,
    respectively.
    25 minipoints (chiitoitsu)
    The final case we cover as part of the basic scoring is scores for a
    chiitoitsu hand. As chiitoitsu is a rather exceptional yaku, it is
    given exceptional minipoints — 25 minipoints. Scores for 25 mini-
    points are summarized in Table 6.5.
    Table 6.5: Scores for 25 minipoints
    Han Ron Tsumo
    Non-dealer Dealer Non-dealer Dealer
    2 1600 2400
    3 3200 4800 800-1600 1600-all
    4 6400 9600 1600-3200 3200-all
    5+ limit hand
    6.2. BASIC SCORING 151
    Since chiitoitsu is itself a two-han yaku, the scoring table only
    starts with two han for ron and three han for tsumo. Again, we mem-
    orize this table column-wise.
    Scores for 25 minipoints
    • ron (non-dealer): 16, 32, 64, mangan
    • ron (dealer): 24, 48, 96, mangan
    • tsumo (non-dealer): 8-16, 16-32, mangan
    All the sequences are a geometric progression, making it rela-
    tively easy to memorize.
    Practice, practice, practice
    This completes the basic methods of score calculation. Memoriz-
    ing all the scores for limit hands as well as the cases of 30, 40, 20, and
    25 minipoints should be more than enough. Of course, no one will
    be able to master this method just by reading and understanding the
    materials in this chapter. You would need to actually practice what
    you have learned, and you will have to do so repeatedly.
    152 CHAPTER 6. SCORING
    bababababababababababababababab
    Notes on pinfu tsumo
    One of the common mistakes that beginners tend to make is to
    claim 1000-2000 for riichi + pinfu + tsumo (mistaking 3 han–
    20 minipoints for 3 han–30 minipoints) or claim mangan for ri-
    ichi + pinfu + tsumo + dora (mistaking 4 han–20 minipoints for
    4 han–40 minipoints). If you have trouble wrapping your head
    around why pinfu + tsumo hands are given lower minipoints,
    knowing the origin of this rule might be helpful.
    The yaku pinfu is realized when a hand has no component that
    generates an additional minipoint. A pinfu hand cannot have a
    set, edge wait, closed wait, single wait, or a pair of value tiles be-
    cause they all generate an additional minipoint. Recall that tsumo
    also generates 2 minipoints. Therefore, logically speaking, pinfu
    cannot be claimed when you win it by tsumo. In fact, some tradi-
    tional mahjong rule sets do not allow a combination of pinfu and
    tsumo. Under such rule sets, when you win a pinfu-only hand
    by tsumo, you are allowed to claim tsumo only, giving you 1 han–
    30 minipoints (20 base minipoints + 2 minipoints for tsumo = 22,
    rounded up to 30 minipoints), which gives you 300-500.
    However, some people thought that this is a bit unfair, claiming
    that a pinfu tsumo hand should be given a higher score than a
    tsumo-only hand. At the same time, they recognized that the score
    for pinfu + tsumo should be lower than that for a “proper” 2-
    han tsumo hand (e.g., tanyao + tsumo). Therefore, they decided
    that pinfu + tsumo should be placed in between these two —
    1 han–30 minipoints (tsumo only; 300-500) and 2 han–30 mini-
    points (tanyao + tsumo; 500-1000) — giving it the score of 400-
  10. Therefore, the score for riichi + pinfu + tsumo (3 han–20
    minipoints; 700-1300) is higher than riichi + tsumo (2 han–30 mini-
    points; 500-1000) but lower than riichi + tanyao + tsumo (3 han–
    30 minipoints; 1000-2000).
    6.3. ADVANCED SCORING 153
    6.3 Advanced scoring
    As I mentioned in the previous section, a hand with one or more
    concealed set of terminal/honor tiles (or its equivalent) or quads
    may have unusually high minipoints, calling for an actual calcula-
    tion of minipoints.
    6.3.1 Minipoint calculation
    Let’s first review the basics of minipoint calculations. All stan-
    dard hands (i.e., hands with melds) have the base 20 minipoints.
    Then, we add the following minipoints depending on how we win
    the hand:5
    • tsumo (open or closed, except for pinfu): 2
    • ron (closed): 10
    • ron (open): 0
    We add further minipoints for each set and quad in a hand depend-
    ing on whether it is a concealed one or an open one. Table 6.6 sum-
    marizes minipoint contributions from a set and a quad.
    Table 6.6: Minipoint contributions from a set and a quad
    Tile Minipoint
    Open Concealed
    set simple 2 4
    terminal/honor 4 8
    quad simple 8 16
    terminal/honor 16 32
    5 As mentioned, there are two exceptions to this calculation rule. First, it is de-
    cided that pinfu tsumo is always 20 minipoints. Second, the so-called “open
    pinfu hand is always 30 minipoints whether ron or tsumo.
    154 CHAPTER 6. SCORING
    Finally, we add 2 minipoints for each of the following, if any.
    • Pair of dragon tiles
    • Pair of seat wind tiles
    • Pair of prevailing wind tiles
    • Closed, edge, or single wait
    When the head of a hand is of seat wind and prevailing wind
    (e.g., ffl for the East player in the East round), we get 2 + 2 = 4 mini-
    points.6 If the wait is either side wait or dual pon wait, we don’t get
    any minipoint for it. As we saw when we discussed wait patterns
    in 3.4, we may get different minipoints depending on which of the
    multiple winning tiles to win on. For example, consider the follow-
    ing hand.
    ȷ%%% +
    The hand is waiting for -. If we win by ron on , we get no
    minipoints for the wait and so this hand has 30 minipoints (base 20
  • 8 for a concealed set of honors + 2 for an open set of simple = 30).
    However, if we win this hand on , we get additional 2 minipoints
    for closed wait. This is because ȷ can be thought of as
    + ȷ. Therefore, the hand has 40 minipoints in that case
    (30 + 2 = 32, rounded up to 40).
    6.3.2 Scores for 50 minipoints or above
    When a hand has one or more concealed set of honor tiles, the
    hand may have 50 minipoints or above. You may want to memorize
    6 This is the case with EMA rules and Tenhou rules, but this is not a universally
    adopted rule.
    6.3. ADVANCED SCORING 155
    the case of 50 minipoints, summarized below. If you are a perfection-
    ist, you may also want to memorize the cases of 70 and 110 minipoints
    as well, but I can assure you that it would not be worth the effort.
    50 minipoints
    Scores for 50 minipoints are quite easy to memorize if you have al-
    ready memorized scores for 25 minipoints (chiitoitsu), summa-
    rized in 6.5. Recall that the score for a 1 han–50 minipoints hand
    should be the same as that for a 2 han–25 minipoints hand.
    Table 6.7: Scores for 50 minipoints
    Han Ron Tsumo
    Non-dealer Dealer Non-dealer Dealer
    1 1600 2400 400-800 800-all
    2 3200 4800 800-1600 1600-all
    3 6400 9600 1600-3200 3200-all
    4+ limit hand
    70 minipoints
    Hands with 70 minipoints do not appear very often (probably once
    in 20 games or so). Table 6.8 summarizes scores for 70 minipoints.
    If you would like to memorize the table, notice that it is sequential
    (until the end): 23 (non-delaer) ! 34 (dealer) ! 45 (non-dealer) !
    68 (dealer).
    110 minipoints
    For the sake of completeness, Table 6.9 summarizes scores for 110
    minipoints.
    156 CHAPTER 6. SCORING
    Table 6.8: Scores for 70 minipoints
    Han Ron Tsumo
    Non-dealer Dealer Non-dealer Dealer
    1 2300 3400 600-1200 1200-all
    2 4500 6800 1200-2300 2300-all
    3+ limit hand
    Table 6.9: Scores for 110 minipoints
    Han Ron Tsumo
    Non-dealer Dealer Non-dealer Dealer
    1 3600 5300 — —
    2 7100 10600 1800-3600 3600-all
    3+ limit hand
    110 minipoints occur only in extremely rare occasions. Consider
    the following hand.
    fflffl%% ffiffi ffi ffi
    Suppose you are in the East round. If the dealer wins this hand by
    ron on %, he gets 20 (base) + 10 (closed hand ron) + 4 (pair of seat &
    prevailing wind tiles) + 4 (open set of honors) + 32 (concealed quad
    of terminals) + 32 (concealed quad of terminals) = 102, rounded up
    to 110 minipoints. The score for 1 han–110 minipoints is 5300.
    If he wins by ron on ffl, on the other hand, he gets more han
    (set of seat & prevailing wind) but lower minipoints. This is because
    the minipoint contribution of the pair of % (2) is smaller than that
    of the pair of ffl (4). Since the score of 2 han–100 minipoints hand is
    the same as that of 3 han–50 minipoints hand, he obtains 9600 points.
    6.3. ADVANCED SCORING 157
    6.3.3 Examples
    Let’s see how scores change as we advance a hand. For each of
    the examples below, try calculating the scores for different winning
    tiles and for tsumo and ron.
    Scoring 1
    %%%
    What are the scores?
    If you win this hand by ron, the hand has 1 han (Red Dragon) and
    40 minipoints: 20 (base) + 10 (closed hand ron) + 8 (concealed set
    of honors) = 38, rounded up to 40, so you get 1300 points.
    If you win it by drawing , the hand has an additional yaku,
    menzen tsumo (Fully Concealed Hand), with 30 minipoints: 20 + 8
  • 2 (tsumo) = 30. You thus get 500-1000 tsumo = 2000 points.
    However, if you win it by drawing , you get 40 minipoints be-
    cause of the additional 2 minipoints for
    closed wait: . You thus get 700-1300 tsumo = 2700 points.
    Let’s say you draw . What would you discard?
    %%% Draw
    If you discard , the wait is - (2 kinds–7 tiles). If you discard
    , however, you get a 3-way wait: - (3 kinds–7 tiles). Let’s
    say you choose the latter, resulting in the following hand. Now, let’s
    think about the scores for each winning tile.
    158 CHAPTER 6. SCORING
    Scoring 2
    %%%
    What are the scores?
    If you win this hand on , the hand is still 1 han–40 minipoints =
  1. However, if you win on or , the three tiles of within
    the hand are treated as a concealed set, giving you 4 additional mini-
    points: 20 (base) + 10 (closed ron) + 8 (set of %) + 4 (set of ) =
    42, rounded up to 50 minipoints. You thus get 1 han–50 minipoints
    = 1600 points. If you win by tsumo, you get 40 minipoints so you will
    get 700-1300 = 2700 points.
    Let’s say you draw . What would you discard?
    %%% Draw
    If you discard , the wait is -. Let’s think about the scores for
    each winning tile.
    Scoring 3
    %%%
    What are the scores?
    If you win the hand by ron on , you get an additional yaku, iipeiko
    (Pure Double Chow), giving you 2 han–40 minipoints = 2600 points.
    If you win the hand by tsumo, the minipoints are now lower than
    before because you have side wait and only one concealed set; we
    6.3. ADVANCED SCORING 159
    cannot think of the three tiles of as a set any more. You get 2 han–
    30 minipoints if you draw (500-1000 tsumo = 2000), whereas you
    get 3 han–30 minipoints if you draw (1000-2000 tsumo = 4000).
    Let’s say you draw . What would you discard?
    %%% Draw
    Discarding is the best option. To understand why, let’s think about
    the scores.
    Scoring 4
    %%%
    What are the scores?
    Notice that the wait and the potential han counts did not change at
    all. However, you get increased minipoints because you now have
    the concealed set of back again. You will get 2 han–50 minipoints
    = 3200 points if you win by ron on . If you draw , you will get
    3 han–40 minipoints, giving you 1300-2600 tsumo = 5200 points.
    Let’s say you draw another . What would you discard?
    %%% Draw
    The best discard is , which makes this hand a toitoi (All Pungs)
    hand, as follows.
    160 CHAPTER 6. SCORING
    Scoring 5
    %%%
    What are the scores?
    The hand has three concealed sets already, giving you at least san
    anko (Three Concealed Pungs) in addition to toitoi and Red Dragon.
    Now you no longer need any tedious minipoints calculation. If you
    win this hand by tsumo, it is yakuman (su anko; Four Concealed Pungs).
    If you win it by ron, you get five han (toitoi, san anko, and Red
    Dragon); it is mangan regardless of minipoints.
    6.4. SCORING TABLES 161
    6.4 Scoring tables
    Table 6.10: Scores for non-dealer
    Minipoints 1 han 2 han 3 han 4 han
    20 — — — —
    — (400-700) (700-1300) (1300-2600)
    25 — 1600 3200 6400
    — — (800-1600) (1600-3200)
    30 1000 2000 3900 7700
    (300-500) (500-1000) (1000-2000) (2000-3900)
    40 1300 2600 5200 8000
    (400-700) (700-1300) (1300-2600) (2000-4000)
    50 1600 3200 6400 8000
    (400-800) (800-1600) (1600-3200) (2000-4000)
    60 2000 3900 7700 8000
    (500-1000) (1000-2000) (2000-3900) (2000-4000)
    70 2300 4500 8000 8000
    (600-1200) (1200-2300) (2000-4000) (2000-4000)
    80 2600 5200 8000 8000
    (700-1300) (1300-2600) (2000-4000) (2000-4000)
    90 2900 5800 8000 8000
    (800-1500) (1500-2900) (2000-4000) (2000-4000)
    100 3200 6400 8000 8000
    (800-1600) (1600-3200) (2000-4000) (2000-4000)
    110 3600 7100 8000 8000
    — (1800-3600) (2000-4000) (2000-4000)
    Note: Numbers in parentheses are tsumo scores.
    162 CHAPTER 6. SCORING
    Table 6.11: Scores for dealer
    Minipoints 1 han 2 han 3 han 4 han
    20 — — — —
    — (700) (1300) (2600)
    25 — 2400 4800 9600
    — — (1600) (3200)
    30 1500 2900 5800 11600
    (500) (1000) (2000) (3900)
    40 2000 3900 7700 12000
    (700) (1300) (2600) (4000)
    50 2400 4800 9600 12000
    (800) (1600) (3200) (4000)
    60 2900 5800 11600 12000
    (1000) (2000) (3900) (4000)
    70 3400 6800 12000 12000
    (1200) (2300) (4000) (4000)
    80 3900 7700 12000 12000
    (1300) (2600) (4000) (4000)
    90 4400 8700 12000 12000
    (1500) (2900) (4000) (4000)
    100 4800 9600 12000 12000
    (1600) (3200) (4000) (4000)
    110 5300 10600 12000 12000
    — (3600) (4000) (4000)
    Note: Numbers in parentheses are tsumo scores.
    Chapter 7
    Riichi judgement
    7.1 To riichi or not to riichi?
    Riichi is a really powerful tool in riichi mahjong. Once you riichi,
    the opponents would have to slow down their attacks or even com-
    pletely fold to avoid dealing into your hand. Therefore, one of our
    top priorities in playing riichi mahjong is to try to make the hand
    ready as fast as possible and call riichi before anyone else does.
    At the same time, however, there are situations where you should
    keep dama (i.e., not calling riichi when having a closed ready hand).
    If you have played mahjong long enough, you must have come across
    many instances where you wondered if you should call riichi or keep
    dama. Knowing when to call riichi is one of the most fundamental
    elements of mahjong strategies, yet it appears this is not very well
    understood among European players. Let’s first review the pros and
    cons of calling riichi.
    Obvious downsides of calling riichi can be summarized as fol-
    lows.
    Demerits of riichi
    • You have to pay 1000 points as a riichi bet.
    • The opponents may play defense and may not discard your
    winning tiles that they would otherwise discard.
    • You cannot change your hand any more; you cannot play
    defense nor improve the wait / scores.
    However, there are many more upsides as well.
    164 CHAPTER 7. RIICHI JUDGEMENT
    Merits of riichi
    • You get one yaku to win.
    • You can expect to increase the score with ippatsu and ura
    dora.
    • The opponents may completely fold or play more defen-
    sively than otherwise. As a result, the opponents may fail
    to make their hand ready, in which case:
    – you will have more opportunities to draw tiles;
    – you are less likely to deal into the opponents.
    • When your previous discards make it look that your win-
    ning tile is safe, riichi may actually increase the chance that
    the opponents discard your winning tile.
    Comparing these pros and cons, it should be evident that calling ri-
    ichi is a low-risk & high-return offense tactic. Moreover, riichi could
    also work as a defense tactic. If you riichi before the opponents do,
    it may prevent them from building a ready hand, which obviously
    reduces your chance of dealing into their hand. Although calling ri-
    ichi means that you can no longer play defensively by choosing safe
    tiles to discard, it poses less of a problem if your defensive skills are
    not very good.
    Riichi judgement criteria I recommend are summarized as fol-
    lows.
    7.1. TO RIICHI OR NOT TO RIICHI? 165
    Riichi judgement
    Choose riichi over dama if at least one of the following three con-
    ditions is met.
  2. Your hand has at least one han other than riichi.
  3. Your hand has a good wait.
  4. You are the dealer.
    This means that you should call riichi if
    • your hand has a bad wait but has one han or more (including
    dora) other than riichi;
    • your hand is riichi-only but with a good wait, or;
    • your hand is riichi-only with a bad wait, but you are the dealer.
    In other words, the only type of riichi that these criteria prohibit is a
    bad-wait riichi-only hand by a non-dealer.
    166 CHAPTER 7. RIICHI JUDGEMENT
    7.2 Insta-riichi
    Keep in mind that, when you call riichi you should do so immedi-
    ately when your hand becomes ready (insta-riichi). There is usually
    no point in waiting for a few turns to have the “right” moment to
    riichi.
    Let me describe a few frequently seen examples where you should
    do insta-riichi. In all the examples that follow, we assume that you
    are the South player in the 6th turn in East-1.
    7.2.1 Examples of insta-riichi
    Pinfu-only hand
    ff a "
    Dora
    You should do insta-riichi with a pinfu-only hand. It is true that this
    hand will have tanyao if you draw ȷ and discard , but waiting for
    that to happen is simply inefficient. Even after you replace with
    ȷ, you will lose tanyao anyway if you win the hand on . Getting
    either ippatsu or one ura dora has a much higher probability than
    drawing ȷ first and then winning on .
    ) Insta-riichi, discarding !
    Bad wait, one dora
    ȷ"""! Dora
    Since this hand has one dora, you should do insta-riichi. Do not shy
    away from riichi even with closed-wait or edge-wait hands. It is true
    7.2. INSTA-RIICHI 167
    that the wait can be improved with as many as four kinds of tiles
    (), but drawing one of those would take about eight more
    turns, on average.1 Since this is a yaku-less hand, you cannot win
    it by ron while waiting in dama. Moreover, even when the wait gets
    improved, this hand will never become pinfu anyway, so the score
    will not be improved.
    ) Insta-riichi, discarding ! !
    1-away from sanshoku
    Red
    ȷa ""ffl
    Dora
    It is true that there are some tiles that can improve the scores and/or
    the wait of this hand. For example, if you draw , the hand will
    have sanshoku (Mixed Triple Chow). If you draw any of ,
    the hand will have pinfu. However, since the hand already has one
    han (red five), you should do insta-riichi.
    ) Insta-riichi, discarding ffl !
    Unconfirmed sanshoku
    "Dora
    You would want to win this hand on (rather than on ) so that
    you can claim sanshoku. However, waiting for without riichi is
    absurd. The worst case scenario is to draw while waiting in dama,
    1 This rough calculation is based on an assumption that the probability of draw-
    ing an arbitrary tile is 1
    34 = about 3%.
    168 CHAPTER 7. RIICHI JUDGEMENT
    in which case you only get 400-700. If you riichi and draw , you
    will get at least 700-1300. With one ura dora or ippatsu you will get
    1300-2600.
    ) Insta-riichi, discarding !
    Riichi-only hand
    ff a ## "
    Dora
    This hand has no yaku or dora, but the wait is good. You can do
    insta-riichi with a riichi-only hand as long as the hand has a good
    wait.
    ) Insta-riichi, discarding !
    Waiting for dora
    a Dora
    You should do insta-riichi even when waiting for dora.
    ) Insta-riichi, discarding !
    When you wonder whether or not you should riichi in a given situa-
    tion, choose riichi. You will be correct most of the time.
    7.2.2 Good wait vs. high scores
    We have discussed in previous chapters the difficult tradeoff we
    face between speed (tile efficiency) and high scores. In riichi judge-
    ment, this tradeoff manifests itself as a choice between (a) having a
    7.2. INSTA-RIICHI 169
    good wait with lower scores and (b) pursuing higher scores with a
    bad wait.
    In the following examples, there are more than one discard candi-
    dates to make the hand ready. I will discuss how to take a balance of
    tile efficiency and hand value in calling riichi. Again, we will assume
    that you are the South player in the 6th turn in East-1.
    Cheap hand
    ff a## "
    Dora
    Calling riichi by discarding makes for a good wait (-; 2 kinds–
    8 tiles), but the hand becomes riichi-only. On the other hand, calling
    riichi by discarding leaves the possibility that the hand has an ad-
    ditional yaku (White Dragon), although the wait is not as good (
    #; 2 kinds–4 tiles). Which one should we choose?
    In cases like this, you should aim for high scores by discarding .
    Discarding and winning on # would double the hand value (ri-
    ichi + White Dragon = 2600 versus riichi-only = 1300), but the prob-
    ability of winning on # would not shrink below half of the proba-
    bility of winning on -.
    ) Insta-riichi, discarding !
    Here is a simple rule of thumb: when the minimum (guaranteed)
    hand value is below 5200 (when won by ron), you should value
    scores over wait. When the minimum hand value is 5200 or above,
    you should value wait over scores. We use 5200 as a cut-point be-
    cause an additional han (roughly) doubles the hand value until it
    reaches 5200.
    170 CHAPTER 7. RIICHI JUDGEMENT
    More expensive hand
    ff a##
    Dora
    This hand has one dora, but the minimum hand value is still be-
    low 5200 (riichi + dora = 2600). Therefore, again, you should value
    scores over wait.
    ) Insta-riichi, discarding !
    Expensive hand
    ff ###$$
    Dora
    With this hand, calling riichi guarantees 5200 (riichi + White Dragon
  • one dora). Therefore, you should value wait over scores this time.
    It goes without saying that riichi is better than going dama.
    ) Insta-riichi, discarding !
    Good wait vs. sanshoku
    aa "
    Dora
    Calling riichi by discarding gives you riichi-only with a good wait,
    whereas calling riichi by discarding gives you riichi + sanshoku
    with a bad wait. Since riichi-only is short of 5200, you should value
    scores over wait.
    ) Insta-riichi, discarding !
    7.2. INSTA-RIICHI 171
    Good wait vs. ittsu
    ȷff "Dora
    Calling riichi by discarding gives you only riichi + pinfu with a
    good wait, whereas calling riichi by discarding gives you riichi
  • ittsu with a bad wait. Since riichi + pinfu is short of 5200, you
    should value scores over wait.
    ) Insta-riichi, discarding !
    Expensive pinfu hand
    Red Red
    ȷffff "
    Dora
    Discarding ff would give you a dama mangan hand with a bad wait.
    That is not too bad, but it is much better to riichi by discarding
    (riichi + pinfu + two red fives = 7700 with a very good wait).
    ) Insta-riichi, discarding !
    Let’s summarize what we have learned so far.
    Good wait or high scores?
    • Scores are more important than wait
    when the minimum hand value is < 5200.
    • Wait is more important than scores
    when the minimum hand value is 5200.
    172 CHAPTER 7. RIICHI JUDGEMENT
    7.2.3 Chiitoitsu waiting for dora
    We will discuss riichi criteria for a chiitoitsu (Seven Pairs) hand
    in this and the next sections.
    Chiitoitsu 1
    %%$$
    Dora
    You should not shy away from riichi with a chiitoitsu hand, es-
    pecially when waiting for dora. Since dora of is something your
    opponents wouldn’t lightly discard even if you keep dama, the chance
    of winning this hand by ron is not very high anyway. Therefore, you
    would rather riichi and aim to improve the score.
    A two-dora chiitoitsu hand can be a game-deciding hand that
    secures you the first place in a game. If you tsumo after riichi, it is at
    least haneman and it can easily be baiman with ura dora (ura dora
    always come in pairs with a chiitoitsu hand). Even when you win
    by ron, it will be haneman with either ura dora or ippatsu.
    ) Insta-riichi, discarding !
    Chiitoitsu 2
    !%%$$ !
    Dora
    Dora in this example is a value-less wind tile, which may be easily
    discarded by your opponents if you keep dama. Nevertheless, you
    should still do insta-riichi by discarding . Aim for haneman or
    baiman rather than being content with 6400.
    ) Insta-riichi, discarding !
    7.2. INSTA-RIICHI 173
    Riichi criteria for chiitoitsu hands waiting for dora are really sim-
    ple.
    Riichi judgement for chiitoitsu
    Riichi any chiitoitsu hand if waiting for dora!
    7.2.4 Chiitoitsu not waiting for dora
    Riichi criteria for chiitoitsu hands get a bit more complicated
    when you are not waiting for dora, summarized as follows.
    Riichi judgement for chiitoitsu
    Do insta-riichi with chiitoitsu (not waiting for dora) if one or
    more of the following holds:
    • You are the dealer;
    • You have tanyao;
    • You have one red five, waiting for a regular five;
    • The wait is a suji-trap wait;a
    • The wait is any tile other than 4, 5, 6;
    • The score without riichi is below mangan.
    a An example of a suji-trap wait is: you are waiting for a 3, and a 6 in the
    same suit is among your discards. See Chapter 8.
    This means that the only two cases where you should go dama are (a)
    when you are a non-dealer and you are waiting for 4,5,6, and (b) you
    have honitsu (Half Flush) or chinitsu (Full Flush) chiitoitsu.2
    2 It is also (theoretically) possible to have tsu iso (All Honors) chiitoitsu. Do
    whatever you want with such a once-in-lifetime hand. I would riichi.
    174 CHAPTER 7. RIICHI JUDGEMENT
    The criteria do not change when your hand already has two dora
    and waits for a non-dora tile.
    Chiitoitsu 3
    !!$$ "Dora
    If you make the hand ready for chiitoitsu, you will be waiting for
    , a non-4,5,6 tile. riichi is better than dama in this case.
    ) Insta-riichi, discarding !
    Chiitoitsu 4
    ȷaa "
    Dora
    Waiting for a 6 is not ideal, but having tanyao justifies riichi. Aim for
    6400 ron or mangan tsumo.
    ) Insta-riichi, discarding !
    Chiitoitsu 5
    Red
    %%$$ "
    Dora
    Likewise, waiting for a 5 is not ideal, but having a red five justifies
    riichi.
    ) Insta-riichi, discarding !
    7.2. INSTA-RIICHI 175
    Chiitoitsu 6
    a $$## "
    Dora
    Since you can get mangan ron or haneman tsumo without riichi, you
    should keep dama with this hand (discard a).
    Chiitoitsu 7
    ȷ$$ "
    Dora
    With this hand, you should keep dama unless you are the dealer.
    However, if you have already discarded & or & a, mak-
    ing for a suji-trap wait, you can call riichi. You can also call riichi if
    your wait is “cheap” in the board (more on this in the next section).
    Why should we refrain from calling riichi with a single wait of
    4, 5, 6? Because of the differences in versatility,3 some tiles make for
    a better single wait than others. Specifically, valueless wind tiles are
    the best candidate for a single wait, followed by value tiles, terminals
    (1s and 9s), and then simple tiles. Among simple tiles, 2s and 8s are
    better than 3s and 7s, and 4,5,6 tiles make for the worst kind of single
    wait.
    Since having 4,5,6 tiles is crucial to utilize red fives, your oppo-
    nents are not very likely to discard them. Moreover, single waits of 4,
    5, 6 are less likely to become a suji-trap wait before or after calling
    riichi, compared with single waits of 1,2,3,7,8,9. A single wait of 4
    requires both 1 and 7 to be discarded to become a suji-trap wait. A
    single wait of 1, on the other hand, only requires 4 to be discarded.
    3 Recall our discussions of tile versatility on in Section 3.2.4.
    176 CHAPTER 7. RIICHI JUDGEMENT
    7.3 When not to riichi
    Keeping a hand dama for no reason is one of the two biggest sins
    in riichi mahjong (the other will be introduced in Chapter 9). Do not
    ever do meaningless dama. To put it the other way around, it is OK
    to keep dama if there is a reason to do so.
    That said, there are not many instances where going dama is better
    than calling riichi. It is thus useful to memorize all these exceptional
    cases; then you should call riichi in all other instances. Here is a list
    of five situations where dama is justifiable.
    Reasons to keep dama
    7.3.1 Bad wait and no dora 7.3.2 In the lead
    7.3.3 Genbutsu wait 7.3.4 Expensive hand
    7.3.5 Many possibilities of improving the hand
    7.3.1 Bad wait
    It is OK to go dama if the wait of your hand is really bad, especially
    when your hand has at least one yaku without riichi so you can win
    it by ron. The question then is, what is a really bad wait? The answer
    depends on three things:
  1. the kinds and the number of winning tiles left;
  2. whether your wait is “expensive” according to your reading of
    the board; and
  3. whether your wait is likely to appear safe in the eyes of your
    opponents.
    7.3. WHEN NOT TO RIICHI 177
  4. The number of winning tiles left
    The first factor to consider is the pure number of winning tiles
    of your hand. The more tiles you can win on, the better the wait is.
    Table 7.1 provides a list of representative waits (roughly) in the order
    of desirability.
    Table 7.1: Typical wait patterns
    Name Example Wait Kinds & Number
    side wait - 2 kinds–8 tiles
    semi side wait - 2 kinds–6 tiles
    stretched single - 2 kinds–6 tiles
    dual pon wait 2 kinds–4 tiles
    closed wait 1 kind–4 tiles
    edge wait 1 kind–4 tiles
    single wait 1 kind–3 tiles
    In general, a wait is said to be good if there are at least two kinds
    and more than four tiles left to win on. Therefore, dual pon wait,
    closed wait, edge wait, and single wait are generally considered to
    be bad waits.
    In counting the kinds and the number of winning tiles for your
    hand, keep in mind that you have to count the kinds and the number
    of live tiles to win on. For example, if your opponents have already
    discarded all the four tiles of somehow, a side wait of - es-
    sentially becomes an edge wait of , leaving only 1 kind–4 tiles to
    win on.
    178 CHAPTER 7. RIICHI JUDGEMENT
  5. Cheap / expensive waits
    However, this is only a part of the picture. When judging whether
    your wait is good enough, you should also take into account the sec-
    ond factor; namely, whether or not your winning tiles are likely to
    be used by other players in their hands. As we learned in discussing
    chiitoitsu hands, middle simple tiles 4, 5, and 6 generally have a
    high chance of being used by the opponents.
    Judging whether certain tiles are likely to be used by the oppo-
    nents also involves a bit of board reading. If your opponents have
    already discarded a lot of tiles in souzu (bamboos), for example, we
    say that souzu are “cheap” in the board. Cheap waits are good waits.
    Suppose three or more of have already been discarded by your op-
    ponents. In such situations, an edge wait of is not bad at all. This
    is because the paucity of makes it rather difficult for anyone to
    utilize in their hand. There is also a good chance that tiles are
    live in the wall. Even when an opponent draws after you riichi,
    they will have difficulty utilizing it in their hand; they have to either
    discard or completely fold.
    Applying the same logic, we can see why honor tiles make for a
    good wait. For example, suppose % had already been discarded and
    you now have a pair of % in your hand. Then, the opponents will
    have difficulty utilizing the last % when they draw it. In a situation
    like this, a dual pon wait of % (and another tile) is almost as good
    as a side wait, despite the fact that the number of tiles to win on is
    smaller.
    On the other hand, when tiles in one suit are not being discarded
    as much as those in the other two suits, that suit is being “expensive”
    in the board. For example, suppose one or more opponents are pur-
    7.3. WHEN NOT TO RIICHI 179
    suing a flush hand (i.e., honitsu / chinitsu) in souzu. Then, even a
    side wait of - can be bad.
  6. Trap waits
    The third factor you may want to consider is whether your wait
    would appear safe in the eyes of your opponents. For example, when
    you have a closed wait of and you have already discarded ,
    there is a good chance that your opponent is tricked into thinking
    that is safe. This is called a suji-trap wait (see Chapter 8). For
    another example, suppose someone has a concealed quad of when
    you happen to have a dual pon wait of and something else. Then,
    the opponents may think that may be safe to discard even when
    it is not.
    That being said, reading the board requires some experience, and
    reading the opponents’ thought is even more difficult. You may want
    to concentrate more on advancing your own hand rather than spend-
    ing too much time trying to read the board. Just keep in mind that
    having a pair/closed/edge/single wait does not automatically mean
    that the wait is bad. Here is a rule of thumb to simplify your decision
    making.
    A reason to keep dama: bad wait
    • Call riichi if there are three or more winning tiles left in the
    board.
    • Go dama if there are only one or two simple tiles left to win
    on.a
    a When waiting for an honor/terminal tile, you can call riichi even when
    only one tile is left in the board.
    180 CHAPTER 7. RIICHI JUDGEMENT
    7.3.2 In the lead
    The second case where going dama may be preferred to riichi is
    when you are ahead of the game by much, and you just want to pro-
    ceed to the next hand or finish the game while keeping your leading
    position. This is especially the case towards the end of the South
    round. For example, let’s say you are in South-4 and the scores are
    as follows:
    East (you) 39000 South 22900
    West 13000 North 25100
    You are currently in a safe lead because even the second ranked
    player (North) cannot defeat you with a mangan tsumo. You can se-
    cure your position even if you deal into a mangan hand by the South
    or the West players. However, if you riichi, the North player can now
    get the first place with a mangan tsumo, and the South player can get
    the first place with a direct hit mangan ron from you. Do not run such
    risks by calling riichi. Even when you get a ready hand with a really
    good wait, you must go dama. For more discussions of what to do in
    South-4, see Chapter 10.
    7.3.3 Genbutsu wait
    The third case where going dama is OK is when another player is
    already getting a lot of attention from others (e.g., riichi, dora pon, or
    honitsu) and one of your winning tiles is among his genbutsu tiles.
    One player’s genbutsu tiles are all the tiles discarded by that player
    and the tiles that are passed up by that player.4
    For example, suppose the dealer has the following hand and dis-
    cards in East-1.
    4 See Section 8.2.1 for a more detailed explanation.
    7.3. WHEN NOT TO RIICHI 181
    Discards
    !

    ffiffiffiffi K## E fflfflG
    Dora
    This is a confirmed 7700 hand (seat & prevailing wind + White Dragon),
    and the hand value can easily go up to haneman (18000) or baiman
    (24000).5 In such a situation, everybody will be paying attention
    to the dealer (as they should). Suppose further that you manage
    to make your hand ready for pinfu, waiting for -. Then, you
    should keep the hand dama, as is one of the dealer’s genbutsu
    tiles. There is a good chance that the other two players fold against
    the dealer completely and try to discard nothing but his genbutsu
    tiles.
    Keep in mind, though, that there is a bad kind of attention as well.
    For example, suppose someone is doing the following.
    ffi @ %%M 1 6
    Suppose further he has already discarded dora. Then, he is getting
    a lot of attention, but no one really cares about him, let alone folds
    against him. In such a situation, you should call riichi even when
    your winning tiles are among his genbutsu. Punish a player who
    makes bad calls like this.
    5 The hand can have (a combination of) the following yaku in addition to
    what’s already visible: toitoi (All Pungs), Green Dragon, Red Dragon,
    dora, honitsu, honroutou (All Terminals and Honors), and shousangen (Lit-
    tle Three Dragons). With this hand, the maximum possible hand value is
    sanbaiman (36000).
    182 CHAPTER 7. RIICHI JUDGEMENT
    7.3.4 High scoring hand
    When your hand is already expensive without riichi (minimum
    of 7700 if playing with red fives; 5200 if playing without red fives), it
    is OK to go dama. Let’s see a few examples.
    Expensive hand 1
    Dora
    You should keep this hand dama because the hand is already expen-
    sive (tanyao + three dora = mangan) and the wait is not very good.
    ) Keep dama, discarding !
    Why should we discard , not (which will make for a suji-trap
    wait)? This is to leave the possibility of improving the wait. If you
    draw or call pon on or the fourth after discarding , the wait
    gets significantly better, as follows:
    Dora

.
5
Note that, to justify dama your hand has to have at least 7700 when
won by ron. This means that (1) your hand has to have at least one
yaku (without it you cannot win by ron) and (2) its value is at least
7700 when winning on a tile that gives you the lowest possible score.
7.3. WHEN NOT TO RIICHI 183
Expensive hand 2
Dora
This hand does not have yaku and so you cannot win by ron without
riichi. You should do insta-riichi with this hand by discarding .
Expensive hand 3
ȷȷ a "Dora
This hand is worth 7700 when winning on (tanyao + pinfu +
sanshoku), but the hand is worth only 2000 if winning on (tanyao

  • pinfu). You should therefore do insta-riichi by discarding .
    When you have an expensive hand, going dama is acceptable but
    calling riichi is also an option, especially when you have a good wait.
    Consider the following hand. Should we riichi?
    Expensive hand 4
    Red
    ȷȷ a Dora
    Discarding , we get a confirmed 7700 hand without riichi. I al-
    ready said above that it is acceptable to keep dama when the mini-
    mum hand value is 7700. However, would calling riichi be even bet-
    ter?
    Riichi criteria for hands like this are as follows.
    184 CHAPTER 7. RIICHI JUDGEMENT
    Riichi judgement for an expensive hand
    • Riichi if you are far behind from other players.
    • Riichi if it is the 6th turn or before and the wait is 2-way
    side wait or better.
    • Riichi if it is the 10th turn or before and the wait is 3-way
    side wait or better.
    • Don’t riichi if the minimum hand value is haneman or better.
    7.3.5 Many possibilities of improving the hand
    It is OK to keep dama when there are many possibilities of further
    advancing your hand. Keep in mind, however, that it is rather rare
    that waiting in dama is worthwhile; doing insta-riichi is still better
    in most instances even when there are some possibilities of advanc-
    ing your hand. It makes sense to wait in dama only when both of the
    following two conditions are met.
    A reason to keep dama: improving the hand
    • It is still an early turn (8th turn or before);
    • There are at least six kinds of tiles that can improve the
    scores and/or the wait,
    or
    there is at least one kind of tiles that can improve the score
    by at least three han in one step.
    Keep in mind that waiting in dama becomes less and less desirable
    towards the end of a hand. After passing the 9th turn (the midpoint
    7.3. WHEN NOT TO RIICHI 185
    of the middle row of your discards), you’d better call riichi even if the
    second condition is met. Remember that the probability of drawing
    a particular tile is very small (roughly 3%).6
    If you decide not to riichi, it often makes more sense to revert the
    hand to 1-away rather than maintaining a ready hand. As we learned
    in Chapter 3, a ready hand can accept fewer tiles than a 1-away hand
    can. For example, consider the following hand.
    ffa
    Since calling riichi by discarding gives you riichi-only with a bad
    wait, you may want to refrain from riichi. However, if you discard
    , the hand can be improved only if you draw or . Moreover,
    even when you luckily draw , the hand is still only riichi + pinfu,
    albeit with an improved wait.
    A more sensible choice here is to discard and revert the hand
    to 1-away, as follows.
    ffa
    This is another example of golden 1-away. This 1-away hand is so
    much better than the ready hand you’d get by discarding . Specif-
    ically, there are four kinds of tiles that can improve the score by at
    least three han.
    • If you draw , the hand is ready for junchan (Terminals in All
    Sets) + sanshoku — mangan without riichi and haneman with
    6 As I mentioned before, when there are four kinds of tiles that can improve your
    hand, it will take (on average) eight turns to draw one of them.
    186 CHAPTER 7. RIICHI JUDGEMENT
    riichi. You may want to go riichi in this case because your pre-
    vious discard of makes for a suji trap wait, although going
    dama is also OK.
    • If you draw , the hand is ready for pinfu + junchan + sanshoku
    — haneman without riichi. You may still want to riichi. It would
    be a shame to win this monster hand on , but doing so with-
    out riichi is the worst.
    • If you draw or ȷ, the hand is ready for pinfu + ittsu —
    7700 with riichi. You should definitely riichi. Going dama with
    this hand is absurd.
    For another (less exciting) example, consider the following hand.
    ȷa "Dora
    Suppose this is the 5th turn in a hand. The choice is between (1)
    discarding to make this hand ready or (2) discarding to revert
    the hand to 1-away.
    It is OK to choose either of the two in this case, but there is one
    thing you should not do. That is discarding without calling riichi.
    If, according to your reading of the board, a closed wait of is good
    enough (e.g., none of has been discarded yet, but lots of other tiles
    in souzu (bamboos) have been discarded), do insta-riichi. Waiting in
    dama with a yaku-less hand is generally a bad move. If you discard
    just to keep the hand ready, the hand cannot be won by ron, and
    it can be improved only if you draw . It makes no sense to have
    7.3. WHEN NOT TO RIICHI 187
    such a hand.7
    If you want to wait and improve the hand, you should discard
    to revert the hand to 1-away. If you draw any of ff (5
    kinds–15 tiles), both the wait and the scores get improved. If you
    draw any of ȷ (4 kinds–11 tiles), at least the wait gets im-
    proved. A basic rule of thumb with a yaku-less hand is as follows.
    What to do with a yaku-less hand
    • Riichi if you make the hand ready.
    • Don’t make it ready if you don’t riichi.
    Yaku-less dama
    In some exceptional situations, it may make sense to wait in dama
    while keeping a yaku-less ready hand.
    a Dora
    This hand has one dora with a bad wait (single wait of or ).
    According to the riichi criteria given at the beginning of this chapter,
    you could call riichi with this hand. In fact, if it is already the 9th turn
    or later, you should definitely do insta-riichi. However, if it is the 6th
    turn or before, waiting in dama by discarding or is an option. If
    you draw any of (7 kinds–21 tiles), the hand be-
    comes pinfu with a semi side wait. Moreover, with ȷ
    7 Of course, if this were towards the very end of a hand (15th–18th turn), it
    would make a lot of sense to have a yaku-less dama hand in order to avoid noten
    penalty.
    188 CHAPTER 7. RIICHI JUDGEMENT
    (7 kinds–28 tiles) the wait will become a stretched single wait. When
    there are this many possibilities of improving a hand (14 kinds–49
    tiles), it is OK to go dama with a yaku-less hand.
    7.4 Glossary
    Insta-riichi is to riichi immediately when a hand becomes ready rather
    than wait for a few turns to riichi. Basically, all riichi should be
    insta-riichi.
    Dama is not to riichi when having a closed ready hand. See Section
    7.3 for cases where going dama might be better than riichi.
    Yaku-less dama is when you have a ready hand with no yaku and
    choose not to riichi. There are very few instances where doing
    so is justifiable.
    Genbutsu are tiles that are safe for a given player, either because they
    were discarded by that player themselves or because they are
    discarded by other players after that player called riichi. See
    Section 8.2.1 in Chapter 8.
    Chapter 8
    Defense judgement
    8.1 To push or to fold?
    Knowing when to push and when to fold is another important
    element of mahjong strategies. Push–fold judgement is a lot more
    complicated than riichi judgement covered in the previous chapter.
    In presenting defense strategies, I will first describe a very simple
    principle that tells you when to be defensive and when to be offen-
    sive, based purely on your hand. After understanding this principle,
    the next step is to understand how to be defensive. The latter part of
    this chapter introduces a set of defensive techniques.
    8.1.1 A simple principle
    A lot of variables can factor into our decision to push or to fold
    against the opponents. You may want to consider, among other things,
    whether or not you currently have a ready hand, the potential hand
    value of your hand, the likely hand value of an opponent’s hand,
    your current rank in the game, the opponent’s standing in the game,
    just to name a few.
    It is simply impossible to take into account these and other impor-
    tant factors all at once in a limited amount of time. Instead, I suggest
    you utilize the following shortcut for push/fold judgement.
    190 CHAPTER 8. DEFENSE JUDGEMENT
    Push/fold judgement
    When another player has a ready hand,
    Push if two of the following conditions are met:
  1. Ready hand;
  2. High scoring hand;
  3. Good wait.
    Fold if two of the following conditions are met:
  4. 1-away (or worse) hand;
  5. Low scoring hand;
  6. Bad wait.
    Let me explain each component of this principle in turn.
    8.1.2 Guessing if an opponent has a ready hand
    First, you need to guess if another player has a ready hand or not;
    if your opponent does not have a ready hand, there is no point in
    playing defensive. Of course, knowing whether an opponent has a
    ready hand can be difficult. Rather than spending too much time
    trying to guess if they have a ready hand, let’s stick with rough but
    simple shortcuts.
    There are three possibilities to consider.
    A. Riichi
    This is the easiest case. You can be fairly certain that the op-
    ponent has a ready hand. We will talk about how to defend
    against riichi in Section 8.3.
    B. Open ready hand
    Knowing whether or not an opponent has an open ready hand
    8.1. TO PUSH OR TO FOLD? 191
    is a bit complicated. We will discuss this in Section 8.4.
    C. Dama ready hand
    We will completely ignore this case.
    Assuming an opponent would not have a dama ready hand is ob-
    viously not always correct. Nevertheless, this shortcut would be ac-
    ceptable given that accurately guessing whether or not an opponent
    has a ready hand is extremely difficult. Part of the reason why it is OK
    to ignore the case of dama ready hand lies in the fact that riichi is such
    a powerful tool in riichi mahjong that calling riichi is strictly better
    than going dama in most instances; it is very difficult for your oppo-
    nents to win a game if they keep choosing dama when they should
    call riichi (and they are likely to know that).
    8.1.3 Three conditions to push/fold
    Note that, according to the principle laid out above, just because
    (you think) an opponent has a ready hand, it does not automatically
    mean that you must fold immediately. Specifically, you should still
    push if two out of the three conditions specified above — ready, high
    score, and good wait — are met.
    The first condition is fairly straightforward. Just remember that
    a clear, firm line should be drawn between having a ready hand and
    having a 1-away (or worse) hand. Pushing with a 1-away hand is
    acceptable only when both of the other two conditions are met.
    The second condition is also straightforward. We say a hand is
    a high scoring one if the minimum hand value is 7700; otherwise it
    is a low scoring hand (recall the discussion in Section 7.3.4 from the
    previous chapter).
    192 CHAPTER 8. DEFENSE JUDGEMENT
    The third condition (good / bad waits) needs some explanation.
    When you have a ready hand, this is straightforward. You can decide
    if the third condition is met simply based on the waits classification
    discussed in Section 7.3.1 from the previous chapter. That is, wait is
    good if it is at least as good as stretched single or semi side wait (2
    kinds–6 tiles); dual pon wait, closed wait, edge wait, and single wait
    are usually considered to be a bad wait.
    The question then is: how do we judge if a hand has a good wait
    when the hand is 1-away or worse? When a hand is 1-away or worse,
    your judgement should be based on the best possible wait pattern you
    can choose when the hand becomes ready in the worst possible man-
    ner. An example will be helpful. Suppose you have the following
    hand when another player calls riichi.
    ȷȷ$$$" $Dora
    This hand is not ready but has the minimum of 7700 point, so your
    decision to push or fold depends on the third condition. Notice that
    this is a perfect 1-away hand; no matter how this hand becomes ready,
    you can always choose to have a side wait. In other words, the best
    possible wait pattern you can choose when this hand becomes ready
    is always a good one. If you draw or pon on ȷ or or chii -,
    you can have a side wait of -. If you draw or chii -, you
    can have a side wait of -. Therefore, you can push to the fullest
    (zentsu) with this hand.
    On the other hand, the following hand is also 1-away from ready
    with a high scoring potential, but it will not always lead to a good-
    wait ready hand.
    8.2. DEFENSE BASICS 193
    Red
    "
    Dora
    Specifically, it will be a side-wait ready hand only if you draw first.
    If you draw - first (which will occur with a much higher proba-
    bility than drawing will), it will be a closed-wait hand. Therefore,
    the best possible wait pattern in the worst-case scenario is not a good
    one. Therefore, you should fold with this hand when you are fore-
    stalled by an opponent.
    For another example, consider a chiitoitsu hand. A chiitoitsu
    hand will always have a bad wait. This means that you should in
    principle fold if an opponent calls riichi when your chiitoitsu hand
    is not ready, even if you have two or more dora in your hand.
    8.2 Defense basics
    Once you understand the criteria to fold, the next thing you need
    to know is how to fold. There are three main ways to identify safe
    tiles to discard.
    8.2.1 Genbutsu and other absolutely safe tiles
    I introduced the term genbutsu in the previous chapter. Strictly
    speaking, genbutsu tiles of player X refer to those tiles discarded by X
    himself. However, if X has called riichi, then all the tiles discarded by
    anyone after riichi (and passed up by X) are also called X’s genbutsu
    tiles.
    Genbutsu tiles of player X are 100% safe against X, but not nec-
    essarily safe against the other two players.1 There are three kinds of
    1 Of course, a tile discarded by all three of your opponents is safe against all three
    players.
    194 CHAPTER 8. DEFENSE JUDGEMENT
    tiles that are 100% safe against all of the opponents.
    • The tile that was just discarded by your left player.
    • A fourth honor tile when there is no possibility of Thirteen Or-
    phans.
    • An absolute “no chance” tile.
    The first kind is fairly straightforward. Because of the furiten rule,
    the tile just discarded by the left player is 100% safe for you to discard
    in the present turn. That tile is not only genbutsu for the left player
    but also a temporary genbustu for the right and the facing players.
    Until their temporary furiten status is lifted, the right and the facing
    players cannot call ron on it.
    The second kind of absolutely safe tile is relatively simple. Sup-
    pose all four of are visible to you (among the discards, in your
    hand, or as a dora indicator). Then, none of your opponents can win
    Thirteen Orphans unless you discard . In such situations, a fourth
    honor tile is 100% safe. That is, ffl is 100% safe for everyone if all the
    other three tiles of ffl are visible to you.
    The third kind, absolute “no chance”, needs some explanation.
    Let me just give you an example here. Suppose all four tiles of , all
    four tiles of , and all three tiles of are visible to you. Then, the
    fourth is 100% safe for everyone because this tile cannot be a part
    of any set, run, or pair. I will explain more about “no chance” tiles in
    Section 8.2.2 of this chapter.
    Of course, it is not always possible to find tiles that are 100% safe
    for the player who has called riichi (let alone for all three opponents).
    Therefore, we need to know how to identify relatively safe tiles by
    8.2. DEFENSE BASICS 195
    relying on suji and kabe (blockade) theories. I will introduce these
    two theories in turn.
    8.2.2 Understanding suji
    When someone calls riichi, the possibility you need to be wary
    of first and foremost is that the opponent has a side-wait hand. It is
    true that players will call riichi even when their wait is worse than
    side wait. However, according to some statistics,2 about two thirds
    of riichi hands have a side wait or better. This is partly because the
    likelihood of choosing dama increases when the wait is bad. Another
    reason is that players seek to retain side-wait protoruns over closed-
    or edge-wait protoruns when choosing tile blocks to maximize tile
    efficiency.
    Suji defense is a defense tactic to avoid dealing into a side-wait
    hand. A suji is a three-tile interval that corresponds to the wait of a
    side-wait hand. For example, when a hand has a side-wait protorun
    , the wait is or . This wait combination of and is
    called - suji. There are 6 suji in each suit, giving rise to 18 suji
    in total. All the six suji and their corresponding side-wait protoruns
    are summarized in Table 8.1.
    Table 8.1: Six suji
    suji protorun suji protorun
    1-4 suji 4-7 suji ȷ
    2-5 suji 5-8 suji ȷff
    3-6 suji 6-9 suji ff
    When is among a player’s genbutsu, we say and ff are suji
    tiles. Suji tiles are safer than non-suji tiles because the furiten rule
    2 See, for example, Identifying Dangerous Suji.
    196 CHAPTER 8. DEFENSE JUDGEMENT
    Table 8.2: suji tiles
    Genbutsu suji tiles
    discarded and ff become safer
    discarded and become safer
    ȷ discarded and become safer
    and ff discarded becomes safer
    and discarded becomes safer
    and discarded ȷ becomes safer
    prohibits a player from calling ron on when is his genbutsu and
    his wait is -. Likewise, when is among a player’s genbutsu,
    and are suji tiles and thus they are safer than non-suji tiles;
    when ȷ is among a player’s genbutsu, and are suji tiles and
    thus they are safer than non-suji tiles.
    Although makes a suji tile, the opposite is not true; in
    itself does not make a suji tile. is no safer than other tiles just
    because is among genbutsu. What negates is the possibility
    of the - side wait, but the -ff side wait is still a possibility.
    becomes safer only when both and ff are among a player’s
    genbutsu. Table 8.2 summarizes combinations of genbutsu tiles and
    tiles that are made safer by them.
    Suji trap
    Keep in mind that suji defense works only against side-wait hands.
    Since players will call riichi even when their wait is worse than side
    wait, we cannot rely too much on suji. When you wait for a tile
    that is a suji tile of some tiles you have discarded yourself, we say
    you have a suji-trap wait. In particular, when your wait is a suji
    tile of the riichi declaration tile, we say it is an immediate suji-trap
    8.2. DEFENSE BASICS 197
    wait. An immediate suji-trap riichi is a rather common occurrence
    in riichi mahjong primarily because of double closed shape (e.g., 135,
    246, 357, etc.). Consider the following hand.
    ȷ$$$
    Dora
    If you call riichi by discarding the ȷ, the hand waits for , which
    is a suji tile of ȷ (immediate suji-trap riichi).
    In general, the reliability of suji is higher for tiles discarded ear-
    lier in a hand. That is, suji tiles of early discards tend to be safer,
    whereas suji tiles of those tiles that are discarded later are more
    dangerous. In particular, suji tiles of the tile discarded upon riichi
    is at least as dangerous as non-suji tiles.3
    For example, suppose an opponent calls riichi in the 7th turn with
    the following discards.
    "$ -
    riichi
    There are three tiles in the discard that create suji tiles.
    • makes and ff suji tiles.
    3 You might wonder about the reliability of suji for those tiles discarded after
    riichi. There is in fact a big disagreement among professional players about
    whether those tiles discarded after riichi make for safe or dangerous suji.
    For example, 渋川 難波 (Nanba Shibukawa; NPM) argues that suji tiles of
    those discarded after riichi are more dangerous than suji tiles of those dis-
    carded before riichi, whereas 石橋 伸洋 (Nobuhiro Ishibashi; Saikouisen) ar-
    gues the exact opposite. However, both schools of thought agree that the very
    tile discarded upon riichi makes for dangerous suji. See http://osamuko.
    com/identifying-dangerous-suji/ for some data analyses.
    198 CHAPTER 8. DEFENSE JUDGEMENT
    • makes and suji tiles.
    • makes and suji tiles.
    Note that and do not create any suji tiles on their own. Among
    these three tiles , suji tiles of are relatively safe, whereas
    suji tiles of are rather dangerous. The reason why suji tiles of
    are dangerous is that players tend to keep double closed shape
    such as a or until the hand becomes ready. Consider
    the following 1-away hand.
    Red
    ȷff
    We would discard rather than . Then, if we draw - first,
    we do insta-riichi by discarding , creating an immediate suji-trap
    wait.
  7. Understanding tile blockade (kabe)
    Another defense tactic to identify safer tiles is to utilize a tile
    blockade (kabe; wall). When chunks of a number tile are visible
    to you, we say these tiles form a blockade; they block a formation of
    runs that contain that tile. Suppose all four of are visible to you,
    either because they have been discarded, they are in your hand, or
    they are used as a dora indicator. Then, none of your opponents can
    have - suji wait, making relatively safe. This is because no
    one can have a protorun in such a situation.
    No chance
    When all four of a number tile are visible, we say we have a “no
    chance” situation, meaning that there is no chance that an opponent
    8.2. DEFENSE BASICS 199
    has a suji wait that contains the tile that forms a blockade. In the
    example above, is a no-chance tile thanks to a blockade of .
    No-chance tiles are safer than a non-suji tile, but keep in mind
    that dual pon wait and single wait of a no-chance tile is still possible.
    A nice thing about no-chance tiles is that their safety does not depend
    on whether it is a suji tile or not. For example, when we have a block-
    ade of , is safe regardless of whether is among genbutsu.
    Note also that is not necessarily safe just because we have a block-
    ade of , for -ff suji wait is still a possibility. Of course, when
    all four of are visible to you and ff is among a player’s genbutsu,
    then becomes safer for that player.
    Table 8.3 summarizes possible blockades Blockade Safe tiles
    None



    ff
    ȷ ff
    ff

    None
    Table 8.3: Blockades
    and the resulting no-chance safe tiles. No-
    tice that each blockade can produce at most
    two sets of safe tiles. It should be easy to
    see how a blockade of 1 does not make any
    tile safer, a blockade of 2 makes 1 safer, and
    that a blockade of 3 makes 1 and 2 safer.
    However, a blockade of 4 makes only 2 and
    3 safer, as it negates 2-5 and 3-6 waits that
    contain 4, but it does not make 1 any safer.
    Similarly, a blockade of 5 makes only 3 and
    7 safer, negating 3-6 and 4-7 suji waits.
    A blockade can negate non-suji waits as well. For example, if all
    four of and all four of are both visible, then a closed wait of
    is impossible. An opponent has to have a dual pon wait or a single
    wait if he is to win on . If, additionally, all three of are visible
    to you as well, then the fourth is 100% safe. Waiting for in this
    situation is simply impossible.
    200 CHAPTER 8. DEFENSE JUDGEMENT
    A blockade can also negate certain yaku, which decreases the
    chance that an opponent has an expensive hand. For example, when
    all four of are visible to you, then an opponent cannot have ittsu
    (Pure Straight) in manzu (cracks). This information can help us de-
    cide whether to discard a non-suji or a non-suji . The chance
    of dealing into an opponent’s hand is equal, but the chance of deal-
    ing into an expensive hand is lower with . A blockade of also
    negates sanshoku of 123, 234, or 345. This information can help us de-
    cide whether to discard a non-suji or a non-suji . Again, the
    chance of dealing into an opponent’s hand is equal, but the chance
    of dealing into an expensive hand is lower with .
    One chance
    When only three of a number tile are visible to you, we have an
    incomplete blockade, making for what’s called “one chance” tiles.
    One-chance tiles are generally safer than non-suji tiles, but not as
    safe as no-chance tiles. The reliability of incomplete blockades de-
    pends on two things.
    First, relying on an incomplete blockade is effective in earlier turns
    but not as much in later turns. Suppose that an opponent calls riichi,
    and is among his discards. Then, because other players are likely
    to discard if they have one, this tile may become an incomplete
    blockade later on. However, an incomplete blockade formed this way
    is not very reliable. When all three players have apparently folded
    and the fourth is still invisible to you, then it is highly likely that
    the riichi’ed player has it. One-chance tiles would become almost as
    dangerous as non-suji tiles in later turns in situations like this.
    Second, one-chance tiles are more reliable when the incomplete
    blockade that makes for a one-chance tile is known only to you, thanks
    8.2. DEFENSE BASICS 201
    to a concealed set or a pair in your hand. On the other hand, one-
    chance tiles that are created by an incomplete blockade in the discard
    pool are not particularly safe. This is because an opponent is more
    likely to choose riichi over dama when one of his winning tiles is a
    one-chance tile and appears safe.
    When we have two incomplete blockade of consecutive number
    tiles, we say they form a “double one chance” situation. For example,
    if three of and three of are both visible, an opponent has to
    have the fourth and the fourth to have - suji wait, which
    is highly unlikely. Therefore, double-one-chance tiles are safer than
    single one-chance tiles.
    Tile blockade: Safety ranking
    No chance > Double one chance > One chance (earlier turns) >
    One chance (later turns) ≃ Non-suji
    Combining blockade and suji
    When we have a blockade of and ff is among a player’s genbutsu,
    we can deny not only - suji wait but also -ff suji wait,
    making safe. Combining the blockade and suji theories like this
    might seem a bit complicated at first, but you will get used to it as
    you play more games.
    202 CHAPTER 8. DEFENSE JUDGEMENT
    8.2.3 Safety ranking
    Based on what we have learned so far, Table 8.5 below provides
    a ranking of tile safety.
    Table 8.5: Safety ranking
    Rank
    100% Genbutsu
    AAA Fourth suji terminal; Fourth honor tile
    AA Third suji terminal; Third honor tile
    AA- Second suji terminal
    A+ Second valueless wind tile; First suji terminal
    A Second honor tile
    BBB Suji 4,5,6; No-chance tile
    BB+ Suji 2, 8
    BB- Suji 3, 7; One-chance tile (earlier turns)
    B First honor tile
    CC Non-suji terminal
    C One-chance tile (later turns)
    DDD Non-suji 2,8
    DD Non-suji 3,7
    D Non-suji 4,5,6
    There is not much difference between ranks if they are given the
    same alphabet. Tiles in the AAA ranking are dangerous only against
    Thirteen Orphans. When Thirteen Orphans is not possible (i.e., there
    are some terminals or honors that are already exhausted), they be-
    come 100% safe. Fourth tiles mean that three of that tile have already
    been discarded. Likewise, third, second, and first tiles mean that two,
    one, or none of that tile have already been discarded, respectively.
    There is a difference between 4,5,6 tiles, 3,7 tiles, 2,8 tiles, and ter-
    minals (1,9) because of the difference in versatility. Non-suji 4,5,6
    tiles are the most dangerous because they can be caught by two dif-
    ferent suji waits. For example, 4 can be caught by a 1-4 suji and a
    8.2. DEFENSE BASICS 203
    4-7 suji, making it doubly dangerous. 3,7 tiles are more dangerous
    than 2,8 tiles because 3,7 can be caught by an edge wait, whereas 2,8
    tiles cannot. terminals cannot be caught by either an edge wait or
    closed wait. Suji 4,5,6 tiles are safer than suji 2,8 tiles because 4,5,6
    make for bad candidates for dual pon wait or single wait.
    204 CHAPTER 8. DEFENSE JUDGEMENT
    8.3 Defense against riichi
    Putting together what we have learned so far, the defense strategy
    against an opponent’s riichi can be summarized as follows.
    Defense against riichi
    • Do not discard Rank D tiles against an opponent’s riichi
    until your hand becomes ready
    (unless your hand has a really good wait and a really high
    score).
    • If you need to push when your hand is 1-away from ready,
    you can discard Rank C or safer tiles. Only if your hand
    has a guaranteed mangan, you can discard Rank D tiles.
    • If you need to push when your hand is 2-away from ready
    or worse, you can discard Rank B or safer tiles.
    • If you cannot satisfy the above criteria, you must completely
    fold (betaori).
    8.3.1 What to discard when you get stuck
    When you cannot identify safe tiles at all, rely on the following
    and try to be as safe as possible.
    Tile chunks
    Discard pairs and concealed sets. Once you get one tile passed
    against a riichi’ed player, you can be safe for the next turn or two.
    Avoid dealing into expensive hands
    If you discard terminals, you can avoid dealing into a tanyao (All
    Simples) hand. Also, try not to discard the dora indicator tile (when
    8.3. DEFENSE AGAINST RIICHI 205
    dora is a number tile) and any tiles close to dora, as well as the dora
    tile itself.
    Tiles outside early discards
    Tiles that are outside those discarded in “early” turns are rela-
    tively safe. Consider the following riichi.
    "$ aD
    riichi
    This opponent discarded in the 2nd turn, which is relatively early.
    This suggests that he is not very likely to have - suji wait. If
    he had a tile block , he would probably have kept it and dis-
    carded something else. This line of argument is obviously not 100%
    reliable. However, if you compare and in the current example,
    is relatively safe.
    8.3.2 Miscellaneous
    Here are some additional factors you may want to take into ac-
    count when deciding whether or not to be defensive, and how much
    defensive you should be.
    Your position in the game
    You should be more defensive when you are ahead of the game,
    while you should be more aggressive when you are behind. This
    should especially be the case in the South round.
    Turn
    You can be more aggressive in earlier turns, whereas you need
    to be much more defensive towards the end of a hand. Suppose an
    opponent calls riichi in the 3rd turn, and your hand is 1-away from
    206 CHAPTER 8. DEFENSE JUDGEMENT
    ready. Since you have 15 more turns to draw, you still have a good
    chance of making the hand ready. In such situations, it may be worth-
    while to be a little bit aggressive against riichi. However, if you have
    only three more turns to draw (i.e., in the 15th turn) and your hand
    is still 1-away from ready, the chance of making a ready hand before
    the hand ends is very low. It is not worthwhile to discard dangerous
    tiles at this point.
    Moreover, in earlier turns, there are many suji that are “alive”,
    which diminishes the probability of dealing into an opponent’s side-
    wait hands. For example, suppose an opponent calls riichi with the
    following discard.
    "$*
    riichi
    So far, only 2 out of 18 suji have been denied by the discards (ȷ-
    and -), leaving 16 suji alive. Suppose you are considering
    whether to discard . Assuming that the riichi’ed player has a side-
    wait hand, the conditional probability of dealing into his hand with
    is only 1
    16 at this point.4
    However, as the hand proceeds, the number of live suji waits
    will decrease, making it more and more dangerous to discard a non-
    suji tile. Suppose that the hand proceeds and the riichi’ed player’s
    discard is as follows.
    4 Since the riichi’ed player may not have a side-wait hand, the joint probability
    that this is a side-wait hand and the hand waits for is even lower than 1
    16 .
    The total probability that the riichi’ed player is waiting for is a bit greater
    than this joint probability because of the possibility of dual pon wait and single
    wait.
    8.3. DEFENSE AGAINST RIICHI 207
    "$*


    Since as many as 16 suji waits have already been denied, there are
    only 2 suji waits that are “alive” ( - and -). Then, the con-
    ditional probability of dealing into his hand with given that he has
    a side-wait hand is now as high as 50%. This gives us an additional
    reason to be more defensive towards the end of a hand.
    Opponent’s style
    If you know the type of opponent you are facing, you may want to
    take that into account. For example, if you know that your opponent
    is an old-fashioned player who calls riichi only when they have a
    good-wait hand, you can rely heavily on suji theories.
    However, if you know that your opponent understands the mod-
    ern riichi strategies as described in the previous chapter, it is more
    difficult for you to guess whether he has a good wait or a bad wait.
    This is because he would not shy away from riichi even with a bad-
    wait hand. You cannot rely too much on suji theories in such situa-
    tions.
    208 CHAPTER 8. DEFENSE JUDGEMENT
    8.4 Defense against open hands
    8.4.1 Guessing if an opponent has a ready hand
    To defend against an open hand, we first need to know if an op-
    ponent has a ready hand or not. Again, we will use some simple
    shortcuts, which hopefully lead us to the right conclusion most (if
    not all) of the time.
    Defense against open hands
    Assume an opponent has a ready hand in any of the following
    situations.
  8. He has three or more open sets / runs.
  9. When he is doing a flush hand, he starts discarding tiles in
    the suit he is supposedly collecting.
  10. He keeps discarding the tile that he draws.
    8.4.2 Estimating the value of an opponent’s hand
    The next thing you need to know is how expensive an opponent’s
    hand is. Although it is practically impossible to infer riichi’ed player’s
    hand value, we can often estimate the hand value of an opponent’s
    open hand. If you can easily see that an opponent’s hand is tanyao-
    only or fanpai-only, there is no need to be defensive.
    Open hands with dora
    An obvious case of an expensive open hand is one with dora tiles.
    For example, if an opponent has an open set of dora, clearly he has
    8.4. DEFENSE AGAINST OPEN HANDS 209
    a four-han (or higher) hand. Also, if you play with red fives, scores
    get expensive quite easily. For example, suppose the dealer has the
    following open hand in East-1.
    Red
    ffiffiffiffiffiffiffi Gfflffl ,
    Then, this hand has at least 5800 (seat and prevailing wind + red
    five). Try not to push too hard against this player.
    Flush hands
    Flush hands (honitsu or chinitsu) tend to get expensive as well.
    Red
    ffiffiffiffi ) , .a
    A hand like above has a minimum of 3900 and a maximum of haneman
    if you deal into it with a souzu tile. You should fold when you draw
    an unwanted souzu tile.
    Value tiles
    Open sets of value tiles also make for an expensive hand.
    ffiffiffiffi K## E fflfflG
    Dora
    This is a pretty scary hand. You should not discard anything other
    than genbutsu tiles.
    210 CHAPTER 8. DEFENSE JUDGEMENT
    Cheap hands
    On the other hand, you can sometimes see that an opponent is
    likely to have a cheap hand. For example, suppose an opponent is
    doing the following.
    ffiffiffiffiffiffiffi / 7
    Dora
    We can see that honitsu and ittsu are impossible and sanshoku is
    unlikely. If all of the dora tiles and red fives are visible to you (in
    your hand or among the discards), you can be pretty sure that this
    hand is inexpensive. It is true that the following is still a possibility.
    ###$$$% / 7
    Dora
    But, you may be able to rule this out if you check what value tiles are
    still alive in the wall.
    8.4.3 Identifying dangerous tiles against open hands
    You can’t win your own hand if you completely fold every time
    an opponent melds. Unless an opponent has an obviously expen-
    sive hand (e.g., three open sets of value tiles, etc.), we would want
    not to fold completely but to discard some tiles that are not particu-
    larly dangerous. It is therefore important to identify dangerous tiles
    against open hands.
    For example, consider the following.
    ffiffiffiffi L$$ E 5
    8.4. DEFENSE AGAINST OPEN HANDS 211
    This opponent probably has a toitoi (All Pungs) hand (otherwise,
    it would be cheap so you can ignore it). If it is toitoi, suji theories
    and blockade theories are completely useless (remember, their pur-
    pose is to avoid dealing into side-wait hands). Most dangerous tiles
    in this situation are “raw” tiles (tiles that are completely invisible to
    you). In particular, you should not discard raw value tiles. As sin-
    gle wait is also a possibility, all honor tiles are generally dangerous
    (unless they are the fourth tile).
    For another example, consider the following.
    ffiffiffiffiffiffiffi E .a
    Dora
    In a situation like this, one possibility is that the opponent has a dual
    pon-wait hand with value tiles on the one hand and dora tiles on the
    other, as follows.
    $$ E .a
    Dora
    Especially when you are facing a “reliable” opponent, there would
    be a good reason (such as having two dora tiles) why he rushed by
    melding a side-wait protorun first.
    212 CHAPTER 8. DEFENSE JUDGEMENT
    8.4.4 Discard upon chii
    We can sometimes identify tiles that are relatively safe or rela-
    tively dangerous against an open hand by paying attention to what
    an opponent discarded upon calling the last chii or pon. Consider
    the following three cases.
    Case 1 chii ! discard a tile in the same suit
    An opponent who had an open set of $ called chii on and
    discarded .
    ffiffiffiffiffiffiffi 5 L$$
    and discarded
    In this case, it is unlikely that this opponent has a wait in the neigh-
    borhood of , so pinzu (dots) tiles such as are rela-
    tively safe.
    Case 2 chii ! discard a tile in a different suit
    An opponent who had an open set of $ called chii on and
    discarded .
    ffiffiffiffiffiffiffi 5 L$$
    and discarded
    In this case, this opponent’s wait is very likely to be in the neigh-
    borhood of the the last discard, . In particular, - suji and
    - suji are extremely dangerous, and a closed wait of a is also
    8.4. DEFENSE AGAINST OPEN HANDS 213
    a possibility.
    Case 3 pon
    An opponent who had an open set of $ called pon on and
    discarded .
    ffiffiffiffiffiffiffi 5 L$$
    and discarded
    In this case, this opponent’s wait can be in any suit; we cannot iden-
    tify which tiles are particularly safe or dangerous.
    What makes these differences? These readings are based on an
    assumption that the opponent has a good 1-away hand before calling
    the last chii or pon. In Case 1, the opponent has the following perfect
    1-away hand before the last chii.
    L$$
    Then, after calling chii on the opponent discards , making the
    neighborhood of relatively safe.
    On the other hand, in Case 2, the opponent has the following
    perfect 1-away hand before the last chii.
    L$$
Summary

Then, after calling chii on the opponent discards , making the
neighborhood of dangerous. In this particular case, the resulting
214 CHAPTER 8. DEFENSE JUDGEMENT
wait is - suji. If the block were instead, the
resulting wait is - suji. If the block were , the
resulting wait is a.
Finally, in Case 3, the opponent has the following perfect 1-away
hand before the last pon.
ff L$$
Then, after calling pon on the opponent discards , making the
wait unrelated to . Notice that, if the opponent calls chii on ȷ
with this hand and discards , the neighborhood of the last discard
becomes dangerous (just like Case 2). Similarly, if the opponent calls
chii on with this hand and discards , the neighborhood of the
last discard becomes safe (just like Case 1).
Discard upon chii
• chii ! discard a tile in the same suit
) the neighborhood of the last discard is safe
• chii ! discard a tile in a different suit
) the neighborhood of the last discard is dangerous
• pon
) wait can be anything
8.5. GLOSSARY 215
8.5 Glossary
Zentsu is to push to the fullest, usually against an opponent’s riichi.
Betaori is to fold to the fullest.
Suji is a three-tile interval that corresponds to the wait of a side-
wait hand. There are six suji: 1-4, 2-5, 3-6, 4-7, 5-8, and 6-9.
See Section 8.2.2.
Suji tile is a tile that is made safe against side wait when a certain
tile(s) is among an opponent’s genbutsu. For example, when
is among genbutsu, and a are safe against a side-wait
hand.
Suji trap is when the wait is a suji tile. When this happens, the
wait is either dual pon wait, closed wait, edge wait, or single
wait.
Blockade (kabe; wall) is formed when three or four of a number
tile are visible to you. When all four of a number tile are visi-
ble, they form a complete blockade, making for no-chance tiles.
When three of a number tile are visible, they form an incom-
plete blockade, making for one-chance tiles.
No-chance tile is a tile that is made safe by a complete blockade.
There is “no chance” that an opponent has a protorun that in-
cludes a tile that is blocked.
One-chance tile is a tile that is made safe by an incomplete block-
ade. There is “one chance” that an opponent has a protorun
that includes a tile that is blocked.
Chapter 9
Melding judgement
9.1 To meld or not to meld?
Melding decisions — to call pon/chii or not to call — depend on
a lot of variables. The most important criteria of all are the following
two.
When not to meld
Do not meld if one of the following two holds.

  1. The hand is both cheap and far from ready.
  2. Melding significantly reduces the hand value.
    I will discuss each of the two in turn, and then discuss exceptional
    situations that justify melding even when the two conditions above
    are satisfied.
    Throughout this chapter, I assume that you are playing with rule
    sets that allow open tanyao. Although older EMA rules did not al-
    low it, revised EMA rules (effective as of April, 2016) now allow
    tanyao to be an open hand. I will also assume that you are the South
    player in the 6th turn in East-1 unless otherwise stated.
    9.1.1 When not to meld 1: cheap and slow
    Melding is acceptable only when your hand is either expensive or
    fast. Melding with a cheap and slow hand is one of the two biggest
    sins in riichi mahjong.1
    1 As we learned in Chapter 7, the other big sin is meaningless dama.
    9.1. TO MELD OR NOT TO MELD? 217
    When we say a hand is “slow”, we mean that the hand is 2-away
    or worse after melding (i.e., 3-away or worse before melding) and
    with a bad wait. Let’s see a few examples.
    Cheap and slow hand
    ff ## Dora
    An opponent discarded # just now.
    You should not call pon in this situation. Even after calling pon, the
    hand is still 2-away from ready with a couple of bad waits, as follows.
    ff K## Dora
    The probability of winning this hand any time soon is not very high.
    What if an opponent calls riichi now? You will have nothing but sim-
    ple tiles between 3 and 7 to discard. It is not worthwhile to discard
    such tiles against riichi when you have a cheap 2-away hand. When
    your hand is cheap and slow, you should worry more about keeping
    safe tiles such as # than about winning the hand.
    Slow but expensive hand
    ff ## Dora
    An opponent discarded # just now.
    This time, you can call pon on # then discard . This hand is still
    slow (after all, the hand shape is exactly the same as before), but it
    has a potential to be 7700 (White Dragon + sanshoku + two dora)
    even when you open it. When you see a high score potential, you can
    meld even with a slow hand.
    218 CHAPTER 9. MELDING JUDGEMENT
    Cheap but fast hand
    ȷ ##
    Dora
    An opponent discarded # just now.
    Again, you can call pon on # then discard . This hand is cheap
    and it will be 2-away after the pon, but all the remaining blocks have
    a good wait. When you can expect to win a hand in no time, you can
    meld even with a cheap hand.
    Melding judgement 1
    Don’t meld with a cheap and slow hand!
    9.1.2 When not to meld 2: big gap in hand values
    You should also refrain from melding when doing so significantly
    reduces the hand value. More specifically, do not meld when the
    hand value drops from 7700 or above to 2000 or below.2
    Cheap but fast hand
    ȷffff
    Dora
    The left player discarded just now.
    Do not meld with a hand like this, at least until the 13th turn or so
    (the third row in the discard). Although calling chii on will make
    the hand ready with a good wait, the hand value reduces to 1000. If
    you keep the hand closed and call riichi, the hand can potentially be
    2 When the hand value reduces from haneman to mangan, or from baiman to
    haneman, melding is acceptable. This is because mangan is already expensive
    enough.
    9.2. MELDING CHOICE: EXAMPLES 219
    a game-deciding hand with a realistic possibility of getting mangan
    or haneman.3
    Fast and expensive hand
    Red
    ȷff
    Dora
    The left player discarded just now.
    Calling chii on will make the hand ready with a good wait and a
    high score (7700). It is true that this hand can be even more expen-
    sive if you keep it closed. However, 7700 is already pretty expensive.
    An additional han does not improve the hand value as much beyond
    4 han. We should thus call chii on , especially after the 9th turn
    or so.
    Melding judgement 2
    Don’t meld if melding significantly reduces the hand value!
    9.2 Melding choice: examples
    We will now see more examples of melding judgements, some of
    which will describe an exception to the two conditions introduced so
    far.
    9.2.1 Eliminating bad waits
    One of the purposes of melding is to eliminate a bad wait in a
    hand to enhance speed. When you can call pon or chii to complete
    a bad-wait block in your hand it often makes sense to do so. More
    3 Riichi + tanyao + pinfu + iipeiko + dora = mangan ron or haneman
    tsumo.
    220 CHAPTER 9. MELDING JUDGEMENT
    specifically, when you call chii with an edge-wait or closed-wait pro-
    torun to make the hand ready, you should meld. Consider the fol-
    lowing hand.
    a$$ !
    Dora
    The left player discarded ff just now.
    You should call chii on ff and discard . It is true that doing so
    means that the hand value will be 1000 (Green Dragon only) and that
    the hand can be won only with $. However, notice that the hand
    value is not very high anyway if you keep the hand closed. Even if
    you draw ff and call riichi, the hand value is 2600 if you win on $
    or 1300 if you win on .
    Keep in mind also that winning a cheap hand like this is not to-
    tally meaningless. This is because doing so also means you prevent
    your opponents from winning their (possibly expensive) hands. You
    do not want to make your mangan hand into a 1000 hand, but the hand
    above is not a mangan hand.
    Moreover, this hand has pretty low tile acceptance (4 kinds–12
    tiles, ff$); the chance of making the hand ready without meld-
    ing is not very high, either.
    Melding judgement 3
    If you can eliminate a bad wait and make the hand ready, meld!
    9.2.2 Improving the wait
    It sometimes makes sense to meld even when your hand is al-
    ready ready, as long as doing so improves the wait and/or the scores.
    9.2. MELDING CHOICE: EXAMPLES 221
    It may also make sense to meld to make a bad-wait 1-away into a
    good-wait 1-away one.
    Improving the wait
    ȷff %%M
    The left player discarded just now.
    The hand is already ready, waiting for . However, you should call
    chii on with ȷff and discard , so you can upgrade the wait
    to a side wait of -ȷ. With melded hands, it is important to think
    about the possibilities of improving the wait and/or scores by meld-
    ing further. In the current example, calling chii on - or pon on
    will improve the wait from a closed wait to a 2-way wait.
    9.2.3 Confirming yaku
    Ideally, we would like to complete a bad-wait block by melding
    so that we can have a good-wait block as the final wait of the hand.
    However, it sometimes makes sense to complete a good-wait block
    by melding if doing so confirms a certain yaku in a hand.
    Confirming yaku
    a Dora
    The left player discarded just now.
    Calling chii on completes a side-wait block in this hand, leaving
    the hand 1-away with one edge-wait and one side-wait protoruns.
    However, this is acceptable because calling chii on confirms ittsu
    in this hand. Getting ittsu with this hand requires that we have ,
    222 CHAPTER 9. MELDING JUDGEMENT
    not a, to complete the protorun . We should thus think of this
    protorun more as an edge-wait protorun rather than a side-wait pro-
    torun. Calling chii on is tantamount to eliminating a bad wait in
    this case.4
    Confirming yaku
    fflfflffl $
    Dora
    The left player discarded just now.
    If you call pon on and discard , the hand is ready. However,
    doing so only gives you a 1300 hand. Instead, you should discard
    after calling pon to have a 1-away honitsu hand, as follows.
    fflfflffl 4 $
    Dora
    You can further call chii on any of or call pon on to get
    5200 or above.
    9.2.4 Concealed set of value tiles
    There are situations where melding with a cheap and slow hand
    may be acceptable. Recall that one of the reasons why melding is not
    worthwhile with a cheap and slow hand is that we will lose safety
    tiles if we meld. When that is less of your concern, melding may be
    an option even with a cheap and slow hand.
    4 Note that you should discard the , not the , after melding. This is because
    we will discard the block if we draw the red .
    9.2. MELDING CHOICE: EXAMPLES 223
    Concealed set of value tiles
    ȷ %%% !
    Dora
    The left player discarded just now.
    This hand is both cheap and slow. Even after calling chii on , the
    hand is still 1-away with a bad wait. However, this hand has a con-
    cealed set of %, which can be used as three safe tiles when someone
    calls riichi. In such cases, you can meld as long as doing so advances
    the hand. That is, you can chii any of ff . You should not
    call chii on -a or pon on , because doing so does not advance
    this hand from 2-away to 1-away or improve the wait/scores.
    Melding judgement 4
    If you have a concealed set of value tiles, you can meld with a
    cheap and slow hand.
    9.2.5 When it is OK to meld with cheap & slow hands
    There are a few more instances where melding with a cheap and
    slow hand is acceptable, summarized as follows.
  3. You are ahead of the game in South-4.
    The hand value is not of your concern in such a situation. You
    can meld with a cheap hand; you can also meld even when
    melding significantly reduces the hand value.
  4. There are two or more riichi bets on the table.
    Winning any hand guarantees a minimum score of 3300 points
    in such a situation, as you get at least 1000 (your hand) + 2000
    for riichi bets + 300 for continuation. This is not much different
    from winning a 3900 hand.
    224 CHAPTER 9. MELDING JUDGEMENT
  5. You are losing and you are the dealer.
    You should aim for calling riichi as soon as possible in order
    to delay the opponents’ attack. However, when you think you
    cannot make the hand ready for riichi soon enough, calling pon
    or chii early may serve the same purpose.
    9.3. CALLING KAN 225
    9.3 Calling kan
    There are three ways to call kan — making a concealed quad
    (ankan), making an open quad (daiminkan), and extending an open
    set to an open quad (kakan). I will discuss decision criteria for each
    of the three cases in turn.
    9.3.1 Concealed quad (ankan)
    The benefits of making a concealed quad includes:
    • another chance to draw a tile;
    • increased minipoints; and
    • possibilities of getting more dora.
    Conditions to justify making a concealed quad includes:
    • 1-away, where at least one block has a good wait;
    • 2-away, where all the blocks have a good wait;
    • you need more dora or more minipoints to improve the place-
    ment (especially in South-4);
    • you are losing badly.
    With this in mind, consider several examples. (Dora is ! in all
    the examples.)
    (1) ȷ """"
    (2) """"
    (3) """"
    226 CHAPTER 9. MELDING JUDGEMENT
    (4) """"#
    (5) """"##
    (1) This hand is 1-away, and one block has a good wait and another
    has a bad wait. You can call kan.
    (2) This is a perfect 1-away hand, so you can call kan.
    (3) This is a perfect 2-away hand, so you can call kan.
    (4) This hand is 1-away, but all the remaining blocks have a bad wait
    (closed wait). You should not call kan.
    (5) This hand is 2-away with a bad wait. You should not call kan
    in normal situations. However, if you are in South-4, and you need
    2000 points to win the game, then you should kan immediately. As
    the hand will have at least 60 minipoints, you can get 2000 points
    with one han (White Dragon).
    Kan judgement 1
    In principle, your hand needs to be close to ready to justify mak-
    ing a concealed quad.
    When not to make a concealed quad
    Calling kan also comes with some cost, including:
    • you may lose safety tiles;
    • the new dora may go to the opponents.
    When the following conditions are present, you should refrain from
    calling kan.
    • the hand is close to ready for chiitoitsu as well;
    9.3. CALLING KAN 227
    • one of the four tiles can be used a good floating tile;
    • you lose some yaku if making the set into a quad.
    Concealed quad?

    It is your turn. What would you do?
    If you call kan, the hand will be 1-away and the wait will not be ter-
    ribly bad; it can be made ready if you draw any of
    a , and you may draw one of these
    tiles as a rinshan tile (the bonus draw after kan). However, the re-
    sulting hand will be either riichi only or riichi + tanyao only, some-
    times with a bad wait.
    If you choose not to call kan and discard , you can treat one
    of the four tiles of as a floating tile that could form a side-wait
    protorun. The hand will be a side-wait ready hand if you draw any
    of . Moreover, if you draw or ȷ, the hand will be
    ready for sanshoku of 456. If you call kan, on the other hand, the hand
    will lose the ability to accept ȷ that would otherwise make
    the hand ready. Therefore, you should not call kan at this point and
    simply discard . You can call kan later if the hand becomes ready
    by drawing a pinzu (dots) tile.
    Concealed quad?
    ffa
    It is your turn. What would you do?
    If you call kan, you will lose pinfu. Moreover, if you draw a tile that
    228 CHAPTER 9. MELDING JUDGEMENT
    completes one of the two side-wait protoruns after calling kan, the
    hand becomes a single-wait hand. You should thus discard . Then,
    if you complete one of the side-wait protoruns first, you can discard
    another to make the hand ready for pinfu.
    Kan judgement 2
    There are cases where we should not make a concealed quad
    even when the hand is (close to) ready.
    9.3.2 Open quad (daiminkan)
    Conditions to justify making an open quad are a little bit more
    demanding than the conditions to justify making a concealed quad.
    You can make an open quad in any of the following situations:
    • the hand is ready with a good wait, and the hand value is be-
    tween 2000 and 5200 points;
    • you need more dora or minipoints to improve the placement
    (especially in South-4);
    • you are losing badly.
    Open quad?
    ȷff%%% 5
    Dora
    The right player discarded % just now.
    This ready hand is currently worth 2000 points with a good wait.
    Calling kan on % is therefore justifiable. If any one of the tiles in your
    hand becomes dora, the hand value increases from 2000 to 5200.
    9.3. CALLING KAN 229
    Open quad?
    %%% 5
    Dora
    The right player discarded % just now.
    This ready hand is currently 2000 points with a bad wait. Calling kan
    on % is not justifiable when the wait is bad.
    Open quad?
    %%% 5 Dora
    The right player discarded % just now.
    This ready hand is currently 1000 points with a good wait. Calling
    kan on % is not justifiable. Even when one of the tiles in your hand
    becomes new dora, the hand value only increases from 1000 to 2600
    points.
    9.3.3 From an open set to an open quad (kakan)
    When you draw the fourth tile of an open set, you have an oppor-
    tunity to extend the open set to an open quad. Conditions to justify
    extending an open set to a quad are more demanding than those for
    a concealed quad but less demanding than those for a regular open
    quad. Doing so is less foolhardy compared with a regular open quad
    because you are not losing four safety tiles. At the same time, this is
    riskier than making a concealed quad because you may be running
    the risk of giving your opponents a chance to get chankan (Robbing
    the Kong).
    You can extend an open set to an open quad in any of the follow-
    ing situations:
    230 CHAPTER 9. MELDING JUDGEMENT
    • the hand is 1-away or better with a good wait, and it has two
    han or more;
    • the hand is 1-away or better, and there are not many turns left
    to draw tiles;
    • you need more dora or minipoints to improve the placement
    (especially in South-4);
    • you are losing badly.
    Open set to quad?
    %M% Dora
    You drew the fourth % just now.
    This 1-away hand has two han and a good wait. Calling kan on % is
    justifiable.
    Open set to quad?
    %M% Dora
    You drew the fourth % just now.
    This hand has three han and a good wait. However, since it is 2-away
    from ready, calling kan on % is not justifiable.
    9.4. MISCELLANEOUS TIPS FOR MELDING 231
    9.4 Miscellaneous tips for melding
    9.4.1 Think ahead
    When you call pon, you have to say “pon! [p´ON]” out loud imme-
    diately and nothing else. There is no such call as “Wait!”, and you
    will have to forgo your call if (1) the next player has already drawn
    their tile before you call pon or (2) another player has already called
    chii before you do.5 This means that you need to think ahead and
    make up your mind about what tile to call before the tile is discarded.
    That is, you should think about what tile(s) can improve the wait
    and/or the scores of your hand all the time. For example, consider
    the following hand.
    Thinking ahead
    ##K
    What tile(s) are you waiting for?
    The hand is ready, waiting for . However, you should also be pre-
    pared for melding further to improve the wait and/or the scores. If
    you draw or call pon on and discard , the wait will be upgraded
    to an irregular 3-way wait of -ȷ . Moreover, if you draw or call
    pon on the red and discard , not only the scores get better but
    also the wait will be upgraded to a side wait of -ȷ.
    Relatedly, think about what to discard upon melding before you
    call. If you are unsure about what to discard upon melding, it prob-
    ably means you should not make the call.
    5 A pon call takes precedence over a chii call, but only if calls are made simulta-
    neously. If the chii call was made well before the pon call, the chii call should
    take precedence.
    232 CHAPTER 9. MELDING JUDGEMENT
    9.4.2 Be ready for dora
    You should also think about how to utilize dora when melding.
    Consider the following hand.
    Utilizing dora
    $L$
    Dora
    The left player discarded just now.
    We should definitely call chii on to make the hand ready, but
    the question here is: should we chii with or with ? Let’s
    compare the resulting hands in each of the two possibilities.
    8 $L$
    8 $L$
    Dora
    Notice that the first hand can accept another dora. That is, if you
    draw , you can keep it and discard to improve the hand value
    from 2000 to 3900. With the second hand, you will have to discard
    the dora when you draw another.
    Calling chii with is better also from a perspective of de-
    fense. Having to discard against an opponent’s riichi is much bet-
    ter than having to discard . can be captured by both - and
    - suji, whereas can be captured only by - suji. More-
    over, even if you deal into an opponent’s - wait, the hand value
    would be lower if you discard than , on average.6
    6 Of course, this is unless an opponent has sanshoku of 678.
    9.4. MISCELLANEOUS TIPS FOR MELDING 233
    9.4.3 Be mindful of the seating
    Each time you take a tile from the facing player (toimen) with a
    pon (or kan) call, the left player’s (kamicha) turn gets skipped. Like-
    wise, each time you take a tile from the right player (shimocha) with
    pon/kan, the facing player’s turn gets skipped. At the same time, the
    right player will have an additional chance to draw a tile in either of
    the two instances. In this sense, your act of calling pon/kan benefits
    the right player while penalizing the left and the facing players. It is
    useful to keep this in mind in making a melding choice, especially
    when the benefit of melding only slightly outweighs the benefit of
    keeping the hand closed in terms of tile efficiency.
    For example, when you are North, you should not meld as ag-
    gressively because doing so will benefit the dealer. Likewise, when
    you are South, you should try to call pon from the facing player (North)
    rather than from the left player (East), so that you can penalize the
    dealer. The same is true when there is a clear front-runner in the
    game. When your right player is much ahead of the game, you should
    try to have a closed hand rather than a melded hand. On the other
    hand, when your left player is leading the game, you should meld a
    bit more aggressively so you can penalize him.
    Seating-related tip 1
    When your right player is the dealer and/or the front-runner, try
    not to call pon too much.
    Applying the same logic, you do not want your right player to
    call pon from your left player. This means that, if you plan to discard
    something that can be pon’ed by the right player, you should do so
    sooner rather than later. For example, suppose you are East, and you
    are deciding which one of the three valueless wind tiles !" to
    234 CHAPTER 9. MELDING JUDGEMENT
    discard in the 1st turn. In this case, you should discard first. If the
    South player calls pon on you discard, that would be much better
    than if he called pon from the North player. Moreover, if you discard
    , there is a good chance that another player may do the same in
    the 1st turn as well, lowering the chance that the South player builds
    a pair of in later turns and calls pon.
    Seating-related tip 2
    When discarding valueless wind tiles, discard the right player’s
    wind first, then the facing player’s wind next.
    Chapter 10
    Grand strategies
    The most important goal in mahjong is to win a game or generally
    improve the placement. I do not deny the inherent joy of winning an
    expensive hand with rare yaku. However, we should always keep
    in mind that winning a hand is just a means to an end; sometimes
    dealing into an opponent’s (cheap) hand can serve our purpose of
    winning the game. In this chapter, I will discuss strategies to improve
    the placement.
    10.1 What to do in South-4
    Most mahjong rule sets adopt some type of uma system where
    players get some extra bonus / penalty points according to the place-
    ment. For example, EMA rules award 15000 points to the first ranked
    player, 5000 points to the second ranked player, 5000 points to the
    third ranked player, and 15000 points to the fourth ranked player.
    Such systems make it clearer that getting a better placement is gen-
    erally more important than simply winning hands.
    Suppose you are currently ranked fourth in South-4, and that the
    third ranked player has 1800 more points than you do. In such a sit-
    uation, winning a 1000 hand is not very meaningful. If you manage
    to add just one more han and win, you will not only get 2000 points
    directly but also get an extra 10000-point bonus for coming in third,1
    a total of 12000-point gain. This is as big as winning a haneman hand.
    In a situation like this, the tradeoff between speed and hand value
    is qualitatively different than usual. For example, when choosing
    1 You will get −5000 points instead of −15000 points, resulting in a net gain of

236 CHAPTER 10. GRAND STRATEGIES
between a good-wait one-han hand and a bad-wait two-han hand,
you should definitely choose the latter. After all, you are essentially
comparing a good-wait 1000-point hand with a bad-wait 12000-point
hand. On the other hand, when choosing between a good-wait two-
han hand and a bad-wait three-han hand, you should choose the for-
mer. Increasing the (virtual) hand value from 12000 to 13900 would
not be worthwhile if doing so significantly diminishes the chance of
winning.
Suppose further that the third ranked player is the dealer. Then,
you will have another option to improve the placement. That is, if
anyone other than the third ranked player gets a mangan tsumo (or
above), you will come in third. This is because the dealer pays 2000
more points than a non-dealer in case of a mangan tsumo. When this
happens, you will lose 2000 points for the mangan payment but gain
10000 points for the placement bonus, resulting in a net gain of 8000
points. This is as big as winning a mangan hand yourself.
Suppose yet further that the second ranked player is the right
player, who is behind the first ranked player by 10000 points. Then,
he will try to get a mangan tsumo because doing so puts him in the
first place. If he is obviously pursuing a honitsu hand, you may want
to discard tiles in the suit he is collecting so he can meld his hand to
get it ready.2 If he indeed gets a mangan tsumo, you will get 8000
points; if he wins by ron from the third ranked player, you will get
10000 points.
That being said, assisting other players in hopes of their getting a
mangan tsumo is more like a last resort. What you should think about
2 Of course, you assist him only until he gets ready. You need to be careful not
to deal into the mangan hand you helped him make.
10.1. WHAT TO DO IN SOUTH-4 237
first and foremost is winning your own hand that is just expensive
enough to improve your placement, which we will now turn to.
Improving the placement by ron / tsumo
As the discussion in the previous section illustrates, you need to
be extra conscious about your placement in South-4. If you are cur-
rently ahead of the game, your top priority is to maintain your place-
ment. If you are behind, you should do your best to improve your
placement as much as possible.
In South-4, the first thing you need to do before the hand begins
is to figure out the point differences between you and other play-
ers. When playing online on Tenhou, this can be easily done any
time by mouse overing the middle board, as illustrated in Section
1.4.4. When playing offline, each player should count and report
their points before the hand begins.
Once you figure out the point differences, you then need to know
how expensive your hand has to be to improve your placement. In
doing so, you need to figure out the required hand values under
three possibilities, as follows.

  1. ron from anyone
  2. tsumo
  3. direct hit ron
    The first possibility to consider is winning your hand by ron from
    anyone (that is, not from the very player you are trying to overtake).
    For example, suppose you are currently ranked second, and the first
    ranked player has 3400 more points. Then, winning a 3 han–30 mini-
    points hand (3900 points) by ron from anyone is sufficient to improve
    238 CHAPTER 10. GRAND STRATEGIES
    your placement. You should thus aim to have a 3-han hand. Since
    you don’t need a 40-minipoint hand, melding is also an option.
    The second possibility to consider is winning your hand by tsumo.
    For example, suppose you are currently ranked second, and the first
    ranked player (non-dealer) has 9500 more points. Then, getting a
    mangan tsumo is sufficient to improve your placement because you
    gain 8000 points while the first ranked player loses 2000 points, in-
    ducing a 8000 + 2000 = 10000 point difference. You should thus aim
    to have a mangan hand and try to win it either by tsumo or by ron
    from the first ranked player.
    The last possibility to consider is winning your hand by ron from
    the very player you are trying to overtake. For example, suppose
    you are currently ranked second, and the first ranked player (non-
    dealer) has 15200 more points. Then, even getting a haneman tsumo
    is not enough. You need a mangan ron directly from the first ranked
    player. This is sufficient because you gain 8000 points while the first
    ranked player loses 8000 points, inducing a 8000 2 = 16000 point
    difference.
    Among these three possibilities, your hand value judgement should
    be based primarily on the first possibility (i.e., winning it by ron from
    anyone). This one requires the highest hand value but it is the most
    realistic. Given that the player you are trying to overtake will try
    hard not to deal into your hand, making your hand value judgement
    based solely on the third possibility (direct hit ron) is too much of a
    wishful thinking.
    With this in mind, consider the following hand. Assume that you
    are the North player in the 6th turn in South-4. You are currently
    10.1. WHAT TO DO IN SOUTH-4 239
    ranked second, and the first ranked player (South) has 5100 more
    points.
    South-4: 5100 points behind, dora ȷ
    ȷ Draw
    What would you discard?
    If you keep and discard , the hand is ready. However, do-
    ing insta-riichi with the current hand is not ideal. Since the hand
    value is only 2600 (2 han–40 minipoints), winning it by ron from the
    third-ranked or fourth-ranked player will not improve your place-
    ment (unless you get ippatsu or ura dora). Also, getting tsumo will
    only give you 1000-2000 (3 han–30 minipoints), generating only a
    4000 + 1000 = 5000 point difference. This is not sufficient to improve
    the placement.
    You should rather keep the hand 1-away by discarding . If you
    draw or , you can then do insta-riichi to get riichi + sanshoku =
    at least 5200 (3 han–40 minipoints). Winning it by ron from anyone
    is now sufficient to improve the placement. If you draw or ff, you
    can also do insta-riichi to get riichi + pinfu + dora. Winning it either
    by tsumo or ippatsu ron is sufficient to improve the placement.3
    Point difference induced by tsumo
    Getting the correct point differences induced by tsumo can be a
    bit complicated. For example, suppose you are the North player,
    currently ranked second in South-4. The West player is leading the
    game, having 6300 more points. In this situation, would winning a
    3 Drawing ff means you are in furiten, but you should still do insta-riichi.
    240 CHAPTER 10. GRAND STRATEGIES
    3 han–30 minipoints hand by tsumo be enough to improve the place-
    ment? What about winning a 3 han–40 minipoints (= 4 han–20 mini-
    points) hand by tsumo?
    To calculate the point difference induced by tsumo, we add the
    points you gain and the points your rival (the first ranked player)
    loses. For instance, the point difference induced by a 3 han–30 mini-
    points hand is: 4000 (your gain) + 1000 (your rival’s loss) = 5000
    points. The point difference induced by a 3 han–40 minipoints hand
    is: 5200 (your gain) + 1300 (your rival’s loss) = 6500 points. In this
    example, getting a 3 han–40 minipoints tsumo is sufficient to improve
    the placement, but getting a 3 han–30 minipoints tsumo is not.
    It would be extremely tedious if we have to do these calculations
    for several possible hand values all in our head in South-4. It would
    be more efficient if we memorize the induced point differences for
    several representative cases; that way, we can use our time and en-
    ergy thinking about other important things during the game.
    Tables 10.1–10.4 below summarize induced point differences for
    limit hands and those with 30, 40 (20), and 50 (25) minipoints. In
    each table, the second column shows the induced point differences
    against another non-dealer, whereas the third column shows those
    against the dealer. Since a dealer pays twice as much as a non-dealer,
    the induced point differences against a dealer are greater. In addi-
    tion, for each counter (continuation) placed on the table, the induced
    point difference will get bigger by 400 points.
    Note that these four tables assume that you are a non-dealer. When
    you are the dealer, you do not usually need to do these calculations
    because you get to continue the game if you win a hand anyway.
    However, when playing with a bankruptcy rule or with time limits,
    10.1. WHAT TO DO IN SOUTH-4 241
    Table 10.1: Limit hands
    Tsumo Non-dealer Dealer
    mangan 10000 12000
    haneman 15000 18000
    baiman 20000 24000
    sanbaiman 30000 36000
    yakuman 40000 48000
    Table 10.2: 30 minipoints
    Tsumo Non-dealer Dealer
    300-500 1400 1600
    500-1000 2500 3000
    1000-2000 5000 6000
    2000-3900 9900 11800
    Table 10.3: 40 (20) minipoints
    Tsumo Non-dealer Dealer
    400-700 1900 2200
    700-1300 3400 4000
    1300-2600 6500 7800
    Table 10.4: 50 (25) minipoints
    tsumo Non-dealer Dealer
    400-800 2000 2400
    800-1600 4000 4800
    1600-3200 8000 9600
    the dealer may not be able to continue the game, in which case even
    the dealer has to consider if winning a particular hand improves the
    placement. Tables 10.5 and 10.6 at the end of this chapter provide a
    summary for a dealer as well.
    Memorizing these tables would be way more important than mem-
    orizing, say, scores for 70-minipoint hands. With these tables in mind,
    consider the following hand. Assume that you are the North player
    in the 6th turn in South-4. You are currently ranked second, and the
    first ranked player (South) has 3300 more points.
    South-4: 3300 points behind, dora
    ff
    Draw
    What would you discard?
    You wanted to draw ȷ first so that you can have riichi + pinfu + one
    242 CHAPTER 10. GRAND STRATEGIES
    dora = 3900. Winning that hand by ron from anyone would improve
    your placement. However, now that you drew , what should you
    do?
    Recall that a 700-1300 tsumo would induce a 3400 point differ-
    ence. Since this is a pinfu hand, getting riichi + pinfu + tsumo
    gives you exactly 700-1300 tsumo. You should thus do insta-riichi by
    discarding . Once you call riichi, you can do either (1) ippatsu
    ron from anyone, (2) direct hit ron from the first ranked player, or
    (3) tsumo to improve the placement.4
    Consider a more complicated example that involves some mini-
    point calculation. Assume that you are the North player in the 6th
    turn in South-4. You are currently ranked second, and the first ranked
    player (East) has 4700 more points. What are the conditions under
    which you can improve your placement with the following hand?
    South-4: 4700 points behind, dora
    $$ : aa/
    What are you waiting for?
    Winning this hand on $ by ron from anyone or tsumo satisfies the
    condition because it gives you 5200 points (toitoi + Green Dragon
    with 40 minipoints). Winning it on , however, only gives you 2600
    points. You can still improve the placement if you get a direct hit
    from the first ranked player, but not if it is from other players. Even
    though the first ranked player is the dealer, you cannot improve the
    4 Whether or not you should let it go when the third or fourth ranked player
    discards your winning tile depends on the point difference between you and
    the third ranked player. Unless it is greater than 12000 points, you should call
    ron and hope to get one ura dora.
    10.1. WHAT TO DO IN SOUTH-4 243
    placement if you draw , either. Declaring tsumo on gives you
    700-1300, which induces only a 4000 point difference even against the
    dealer.
    However, if you manage to draw or a, you should extend the
    melded set to a melded quad. Doing so not only gives you a chance
    of rinshan tsumo or new dora but also enables you to improve the
    placement when drawing . This is because the hand will have 50
    minipoints if you tsumo: 20 for the base minipoints + 8 for a melded
    Kong of or a + 2 for a melded set of a or + 4 for a concealed
    set of + 2 for a pair of $ + 4 for a concealed set of + 2 for
    tsumo = 42, rounded up to 50 minipoints. A 2 han–50 minipoints
    tsumo induces a 4800 point difference against the dealer.
    Maintaining your placement
    If you are ahead of the game in South-4, you should do your best
    to maintain your current rank. Trying to win a cheap but fast hand
    to end the game is an option, but be extra careful not to deal into an
    opponent’s expensive hand. For example, suppose you have 15200
    more points than the second ranked player. If neither you nor the
    second ranked player is the dealer, he cannot defeat you even with
    a haneman tsumo. Then, what you need to be wary of the most is
    to give him a direct hit mangan ron. You will lose not only the 8000
    points for the mangan payment but also the 10000 bonus points for
    the placement, a total net loss of 18000 points.
    In order to figure out what exactly you should do when you are
    ahead of the game in South-4, try to imagine what each of your oppo-
    nents aims to do. Recall the situation I described in discussing riichi
    judgement in Section 7.3, reproduced below.
    Let’s think about the incentive structure for each of the other three
    244 CHAPTER 10. GRAND STRATEGIES
    East (you) 39000 South 22900
    West 13000 North 25100
    players in turn. First, the fourth ranked player (West) should try to
    have a mangan tsumo, for that would put him in the third place. The
    third ranked player (South) would need a 500-1000 tsumo or 2600
    ron to get the second place, which is a realistic goal to pursue. In
    order for him to get the first place, he would need either a haneman
    tsumo or a direct hit haneman ron from you. Finally, in order for the
    second ranked player (North) to get the first place, he would need
    a haneman tsumo or a direct hit mangan ron from you. Given that he
    has only 2200 more points than the third ranked player, the second
    ranked player should rather aim to win whatever hand possible to
    maintain the current rank.
    So, what should you do in such a situation? What you should be
    afraid of the most is a haneman tsumo by South or North. However,
    notice that South and North are in a fierce competition among them-
    selves. Take advantage of this. If winning a fast hand yourself does
    not seem possible, you should try to assist the South player. Since the
    South player is your right player, you should discard versatile mid-
    dle tiles (3–7) so that he would call chii on them, possibly with a
    red five (because South needs 2 han). Recall that even giving him a
    direct hit mangan ron will secure you the first place.
    10.2 What to do by South-3
    It is never too early to start paying attention to your placement.
    If you are behind other players, the target point difference you should
    achieve before the beginning of South-4 is 10000 points or fewer. Over-
    taking with a 10000 point difference in a single hand is a tough but
    10.2. WHAT TO DO BY SOUTH-3 245
    not unrealistic goal; you can do so either by mangan tsumo or haneman
    ron.
    Suppose the dealer wins a mangan tsumo in East-1. Now he is
    leading other players by 16000 points, which is a bit depressing. How-
    ever, instead of trying to overtake him with a single expensive hand,
    you should aim to reduce the point difference from 16000 to 10000
    by the end of South-3. This is a more realistic goal; keep calling riichi
    with a pinfu-only hand, and you will eventually get tsumo + one ura
    dora which induces a 6500 point difference.
    On the other hand, if you are ahead of the game, you should aim
    to have a 10000 or greater point difference with the second ranked
    player in South-4. For example, consider the following hand. Sup-
    pose you are the North player in the 6th turn in South-3. You are
    currently ranked first, and you only have 1000 more points than the
    second ranked player (West).
    Riichi judgement in South-3: dora ȷ
    ȷff aa"
    Riichi or dama?
    The choice here is between keeping the hand dama to maximize your
    chance of winning the hand or calling riichi to aim for a bigger point
    difference. You should do insta-riichi in such a situation. If you
    win this hand by dama ron, the point difference will only be 3600 in
    South-4. Having a 3600 point difference is not much different from
    having a 1000 point difference from the perspective of the second
    ranked player. However, if you win this hand with riichi, the point
    difference will be at least 6200 in South-4, 9000 if you get one ura
    246 CHAPTER 10. GRAND STRATEGIES
    dora, and 11000 if you tsumo. Having a point difference of 11000 in
    South-4 significantly increases your chance of winning the game.
    If you will be the dealer in South-4, the target point difference
    with the second ranked player is 12000 or more, not 10000. This is
    because a mangan tsumo by a non-dealer induces a 12000 point dif-
    ference against the dealer.
    You should also be mindful of induced point differences by noten
    penalties in South-4 and South-3. The maximum point difference in-
    duced by noten penalties is 4000 (1-player noten and 3-player noten).
    This means that you should aim to have at least 4000 point differ-
    ence by the end of South-3. For example, suppose you are leading
    the game in South-4 and you are the dealer. If the hand ends in
    exhaustive draw and the point difference between you and the sec-
    ond ranked player is more than 4000 points. Then, you should de-
    clare noten (not ready) and terminate the game even when you have
    a ready hand. You will not have this option if the point difference is
    fewer than 4000 points.
    10.3. TABLES FOR INDUCED POINT DIFFERENCES 247
    10.3 Tables for induced point differences
    Table 10.5: For non-dealer
    Tsumo Non-dealer Dealer
    300-500 1400 1600
    400-700 1900 2200
    500-1000 2500 3000
    700-1300 3400 4000
    800-1600 4000 4800
    1000-2000 5000 6000
    1300-2600 6500 7800
    1600-3200 8000 9600
    2000-3900 9900 11800
    2000-4000 10000 12000
    3000-6000 15000 18000
    4000-8000 20000 24000
    6000-12000 30000 36000
    8000-16000 40000 48000
    Table 10.6: For dealer
    Tsumo Non-dealer
    500 2000
    700 2800
    1000 4000
    1300 5200
    1600 6400
    2000 8000
    2600 10400
    3200 12800
    3900 15600
    4000 16000
    6000 24000
    8000 32000
    12000 48000
    16000 64000
    Appendices
    248

Chapter A
Manners for offline playing
Manners are meant to make the game of mahjong a pleasant ex-
perience. They are a collection of small tips and techniques the fore-
runners have developed to avoid unnecessary troubles. I present
manners for four different phases of a game — (1) dealing tiles, (2)
drawing and discarding, (3) calling, and (4) winning a hand. Each
entry is given a rank, from one star (∗) to three stars (∗∗∗). Three-star
manners are more important; you should try to acquire three-star
manners first, and then move on to practice two-star and one-star
ones.
A.1 Dealing tiles
1-1: Shuffling ∗∗
I recommend a 2-step shuffling approach. First, shuffle tiles re-
ally hard. Don’t worry about keeping the tiles face down at this point.
This will guarantee that sets, runs, and pairs from the previous hand
are really broken apart. Second, put all the tiles up-side down and
shuffle them face down gently. This will guarantee that no one re-
members the locations of certain tiles.
1-2: Push the wall forward ∗∗
Once you build a wall, push it forward a little so that the facing
player can easily reach your wall. If you push it forward too much,
you will lose the space for discards.
1-3: Tilt the wall ∗
When pushing the wall forward, it would be better if you tilt the
wall a little, as follows. This will make it even easier for the facing
A.1. DEALING TILES 251
player to pick a tile from your wall.
ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi
1-4: Split the wall ∗
In addition to tilting, some players like to mildly split the wall
into three blocks upon building the wall. You get six tiles on the left,
five tiles in the middle, and another six tiles on the right, illustrated
as follows.
ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi
This will make it significantly easier for the dealer to identify the
breaking point in the wall.
1-5: Break the wall ∗
After rolling the dice, the dealer should break the wall himself.
When the dice indicate a number k that is greater than 7, it is easier
to count 15 k tiles counterclockwise rather than counting k tiles
clockwise after identifying which wall to break. For example, when
the dice roll is 9, the dealer should count 6 tiles counterclockwise
(i.e., 6 from the left edge), leaving 6 tile pairs on the left of his wall.
Likewise, when the dice roll is 10, the dealer should count 5 tiles
counterclockwise, leaving 5 tile pairs on the right of the right player’s
wall (right from the dealer’s view, left from the right player’s view).
1-6: Put the rinshan tile down ∗∗
After breaking the wall, the rinshan tile (the first replacement
tile) should be preemptively put down. This is to prevent it from
falling over. This should be done by the player who has the dead
wall in front of him.
252 APPENDIX A. MANNERS FOR OFFLINE PLAYING
1-7: Turn over the dora indicator ∗∗∗
Immediately after putting down the rinshan tile, the dora indica-
tor should be turned over. Doing so is way more important than, say,
separating the dead wall from the end of the wall (which is com-
pletely unnecessary especially at the beginning of a hand). In my
experience, European players somehow like to do the latter first and
don’t open the dora indicator even after they finish the dealing.
1-8: Look at the tiles ∗∗
As you take tiles from the wall during the initial dealing, you
should start taking a look at them. Don’t wait until you get all thir-
teen tiles; doing so is a waste of time not only for you but also for the
other players.
1-9: Dealer’s first discard ∗∗
The dealer should not discard a tile until the North player gets
all thirteen tiles. This is to give everyone a roughly equal amount of
time to decide whether to call pon / chii / ron on the first discard.
A.2 Drawing and discarding
2-1: Don’t use both hands ∗∗
During the play — after the dealing is done and before the hand
finishes —, you should use only one hand. If you are right-handed,
you should not put your left hand on the table, either. Don’t do
things like drawing with your left hand and discarding with your
right hand. This is to prevent (the appearance of) cheating. The
only occasions where using both hands during the play is acceptable
are (1) when sorting the tiles in your hand, and (2) when revealing
your hand upon winning or in cases of exhaustive draw and four-
riichi abortive draw.
A.2. DRAWING AND DISCARDING 253
2-2: Arrange the discards ∗∗∗
Discards should be arranged in an orderly way (six tiles in a row).
2-3: Discard before sorting ∗
You should discard a tile before you put the tile you draw into
your hand. Putting the newly drawn tile into your hand upon tsumo
is a serious violation. To avoid it, you should make a habit of not
putting a newly drawn tile into your hand immediately.
2-4: Let go of the discard ∗∗
Upon discarding a tile, you need to let it go immediately and not
keep your finger on the tile. This is to guarantee that all the other
three players can see which tile you discarded all together.
2-5: Don’t take an overly long time ∗
Keep in mind that three other players are waiting for you; you
should not take an overly long time to draw / discard. In particular,
beginners may want to pay attention to the following.
• When your turn comes, draw a tile immediately (unless you
need to think about whether to call the last discarded tile).
• Once you make up your mind about what to discard, discard it
immediately.
2-6: Don’t speed other players ∗∗∗
Yes, it could be irritating if someone is taking a long time, but be
considerate. You should not press other players to be faster than they
could.
254 APPENDIX A. MANNERS FOR OFFLINE PLAYING
A.3 Calling
3-1: Vocalize clearly ∗∗∗
When you call pon [p´ON], chii [tS´I:], kan [k´2N], riichi [r´I:tS], ron
[r´ON], or tsumo [ts´umo], utter the word clearly so the other three play-
ers can hear you.
3-2: Vocalize before taking an action ∗∗∗
When calling pon, say “Pon.” first before taking the tile. Likewise,
when you call riichi, say “Riichi.” first before discarding a tile and
placing a riichi bet (see also 3-4 below).
3-3: Wait before calling chii ∗
When calling chii, wait for 1 second before uttering the word.
On the other hand, when calling pon / kan / ron you must do so
immediately. If someone says chii first (after taking 1 second), other
players should not be able to call pon / kan / ron. Pon, kan, and ron
should take precedence only if calls are made concurrently.1
3-4: Calling riichi ∗∗∗
The procedure to call riichi is as follows.

  1. Say “Riichi.”
  2. Discard a tile, rotating it sideways.
  3. Confirm that no one calls ron on the discarded tile.
  4. Place a riichi bet.
    The most important point is that you say “Riichi.” before discarding
    a tile. This is because the opponents’ choice of what to do with your
    1 EMA rules allow a pon call to occur even after a chii call is made. I think this
    should be changed.
    A.4. WINNING A HAND 255
    discard (i.e., whether or not to call pon on it, etc.) may be different if
    you riichi.
    A.4 Winning a hand
    3-1: Vocalize clearly ∗∗∗
    When winning a hand, you need to say ron or tsumo clearly. It is
    also OK to say “mahjong” instead.
    3-2: Don’t put the winning tile into the hand ∗∗∗
    When winning by tsumo, don’t place the winning tile inside the
    hand. Just place the winning tile right next to your hand. This is im-
    portant because scores (yaku and minipoints) may be different de-
    pending on which tile was the one to complete the hand.
    3-3: Don’t take the winning tile ∗
    When winning by ron, some European players grab the winning
    tile and place it right next to their hand. Don’t do it. You should re-
    frain from doing this to prevent (the appearance of) cheating. People
    do this on TV, but they do so only for the camera.
    3-4: Sort the tiles before revealing your hand ∗∗
    You need to sort the tiles before showing your hand, so that other
    players can easily check your hand’s score and possible furiten vio-
    lation. Do not split the hand into constitutive groups. Doing so may
    actually obstruct other players’ vision.
    3-5: Declare yaku ∗∗
    After revealing your hand, reveal the ura dora if you have called
    riichi. You need to show the ura dora to all the other players even
    when you don’t get any of them. This is to make sure that you are
    256 APPENDIX A. MANNERS FOR OFFLINE PLAYING
    not underreporting your hand value.2 After that, you should declare
    all the yaku in your hand.3
    3-6: Declare the score ∗∗∗
    You need to declare the score of your hand yourself. It is OK
    to get other players’ help on scoring, but you need to be the one to
    declare it. When declaring tsumo scores, say the payment by a non-
    dealer first, followed by the payment by the dealer. For example,
    when declaring a 300-500 tsumo, say “Three hundred, five hundred.”
    rather than “Five hundred, three hundred.”
    3-7: Confirm the score ∗
    When one player wins a hand, the other three players must also
    see the hand and confirm the declared score. You should also check
    if the hand was not furiten.
    3-8: Payment ∗
    A standard stick set would include four kinds of sticks, as follows.
    100 point 1000 point
    5000 point 10000 point
    In addition to these, I suggest you prepare a set of four 500-point
    sticks. I usually use green 100-point sticks that I bought in Japan,
    2 It may sound odd, but there are situations where you have strategic incentives
    to underreport your hand value. Trying to avoid bankruptcy of another player
    when you are still ranked second or third is one obvious example. For another
    example, players may not want to change the placements of other players in a
    game if they are competing for ranking at a tournament. Underreporting the
    hand value is usually illegal.
    3 Some people may say that you only need to declare the score and that declaring
    yaku is either unnecessary or even undesirable. I personally think it’s unnec-
    essary, especially when playing with experienced players. However, given that
    not everyone at the table can quickly identify all the yaku in another player’s
    hand, it would be prudent if the winner declares all the yaku.
    A.4. WINNING A HAND 257
    which look like: .4 If you don’t have any green sticks,
    you can use anything (e.g., coins, poker chips, etc.) for substitute.
    Having 500-point sticks would make stick payment much more effi-
    cient.
    To streamline the payment, you should try to minimize the num-
    ber of sticks exchanged on the table. Here are two examples of effi-
    cient method of payment.
    3900 ron
    When a player wins a 3900 hand, the player who discarded the
    winning tile gives the winner one , and the winner
    gives back 1100 points with one and one .
    5200 tsumo
    When a player gets a 1300-2600 tsumo, the most efficient and beau-
    tiful method of payment is as follows.
  5. The first non-dealer (the one sitting closer to the winner) pays
    the exact amount with one and three .
  6. The second non-dealer gives the winner 1500 with
    one and one .
  7. The winner gives back the second non-dealer 200 with
    two of the three he got from the first, which en-
    sures that the second non-dealer pays 1300.
  8. The dealer gives the winner 5100 with one and
    one .
    4 The image of 500-point stick was created by someone known as “381654729”
    (Tenhou ID: 零面聴). I thank him for letting me use it in this book.
    258 APPENDIX A. MANNERS FOR OFFLINE PLAYING
  9. The winner gives back the dealer 2500 with the two
    he got from the two non-dealers and the one he
    got from the second non-dealer, which ensures that the dealer
    pays 2600.
  10. After all the exchanges, what remains on the table is exactly
    5200 with one and two .
    For this to work out perfectly, everyone needs to be on the same page.
    It may sound complicated at first, but it sure feels good when the four
    players manage to make it happen together.
    3-9: Exhaustive draw ∗
    In case of exhaustive draw, the dealer should be the first one to
    declare whether or not he has a ready hand. If he wants to declare
    ready, he has to show the hand and say “Tenpai.”; if not, say “Noten.”
    or “Not tenpai.” without showing his hand. Then, South, West, and
    North declare tenpai or noten in that order.
    The order of declaration could make a difference in some (rare)
    occasions. Declaring first is advantageous in some instances and dis-
    advantageous in others. Suppose the dealer is ranked first in South-
    4, having 2900 more points than the second ranked player. Suppose
    further that he has a ready hand. In such a situation, the dealer has
    an incentive to make a declaration after the second ranked player. If
    the second ranked player declares noten, the dealer would want to
    declare noten to terminate the game.5 On the other hand, if the sec-
    ond ranked player declares tenpai, the dealer would want to declare
    tenpai and continue the game. This is because the induced point dif-
    ference in case of tenpai–noten is either 3000 (2-player tenpai) or
    5 Continuing the game means he runs the risk of losing the placement bonus
    (10000 in EMA rules) and the oka points (if any).
    A.4. WINNING A HAND 259
    4000 (1-player tenpai or 3-player tenpai), each of which exceeds the
    current point difference of 2900.
    Declaring first can be advantageous only when playing with a
    bankruptcy rule. Suppose one player is at the verge of bankruptcy,
    having only 1300 points. Suppose further that both he and the first
    ranked player have already declared noten. In such a situation, if the
    second ranked player declares tenpai first, the third ranked player
    would have to declare noten even when he has a ready hand. Oth-
    erwise, the fourth ranked player goes bankrupt and the game is ter-
    minated.
    Because of these advantages and disadvantages of declaring first,
    we should stick with the predetermined order for the sake of fairness.
    Chapter B
    Further readings
    B.1 Books on riichi mahjong
    If you are a complete beginner, I recom-
    mend:
  11. Jenn Barr. 2009. Reach Mahjong: The
    Only Way to Play. Huntington Press.
    There are a few English books on WWYD
    (What would you discard) problems.
    Working on WWYD problems would be a
    good next step after finishing my book.
  12. Takunori Kajimoto. 2001. Mahjong: Kaji Mahjong Special Train-
    ing.
  13. Takunori Kajimoto. 2008. Mahjong Discard Quiz.
  14. Takunori Kajimoto. 2011. Mahjong Threefold Quiz.
  15. Jenn Barr and Garthe Nelson (ed. Gemma Sakamoto). 2013. A
    Riichi Mahjong Study Book. Reach Spirits Inc.
    B.1. BOOKS ON RIICHI MAHJONG 261
    Of these four books, I recommend the last one, written and edited
    by three Western professional players with the Japan Professional
    Mahjong League. The book contains WWYD problems and discus-
    sions as well as quizzes about tile efficiency, waits, and score calcu-
    lation.
    Their WWYD discussions are a lot more multidimensional com-
    pared with stylized hand examples introduced in my book. You
    would find it interesting to see how Jenn and Garthe often disagree
    about what they would discard. Even those players who share a sim-
    ilar view on strategy principles can still disagree about exactly how
    to apply these principles in a given situation. You would be able to
    understand their WWYD discussions much better after completing
    my book first.
    Scott D. Miller, a riichi player from Texas, has recently published
    two books on the history, culture, rules, and variants of riichi mahjong.
    I have not had a chance to read them, but both of them seem to be a
    fun reading.
  16. Scott D. Miller. 2012/2015. Mahjong From A To Zhú. (2nd edi-
    tion) Lulu.com
  17. Scott D. Miller. 2015. Riichi Mahjong: The Ultimate Guide to the
    Japanese Game Taking the World By Storm. Lulu.com
    262 APPENDIX B. FURTHER READINGS
    B.2 Online resources
    Osamuko: http://osamuko.com/
    Osamuko is one of the most extensive online mahjong blogs in
    English. There are quite a few blog entries there, and many of them
    are very good. In particular, I find the articles by a contributor named
    UmaiKeiki very useful.
    Osamuko’s Facebook group: Osamuko's Mahjong Group | Facebook
    There is a Facebook group page hosted by one of the contribu-
    tors of Osamuko. It is a closed group, but I suppose anyone can join
    the group by sending a request to the administrator. Group mem-
    bers frequently post their play records from Tenhou and ask for other
    members’ opinions on them.
    Mahjong on Reddit: Reddit - Dive into anything
    Reddit is a social bookmarking website that allows users to add,
    annotate, edit, and share bookmarks of web documents. It has a
    lively community dedicated to mahjong where you can discuss mahjong
    related topics.
    Mahjong News: http://mahjongnews.com/
    The website is updated regularly with information on upcoming
    mahjong tournaments (Riichi, MCR, and online), their results, and
    newly released mahjong books, among other things.
    Japanese Mahjong Wiki: http://arcturus.su/wiki/
    This website provides an encyclopedic information on rules, ter-
    minology, and strategies of riichi mahjong. It is a wiki page so anyone
    can edit the contents.
    B.2. ONLINE RESOURCES 263
    Reach Mahjong of New York: http://mahjong-ny.com/
    This website not only serves as the hub webpage for players in
    the US but also provides quite a few useful resources, including a
    terminology list, beginner’s guide, and quizzes about tile efficiency
    and scoring.
    Just Another Japanese Mahjong Blog:
    Just Another Japanese Mahjong Blog
    This website has a number of articles on Riichi theories, trans-
    lated from Chinese.
    ReachMahjong.com: http://reachmahjong.com/en/
    This website is run by the professional players who wrote the
    aforementioned Riichi Mahjong Study Book. You can find more WWYD
    problems and discussions, strategy guides, and reports on tourna-
    ments, among other things.
    EMA: http://mahjong-europe.org/
    This is the official webpage of the European Mahjong Associa-
    tion. You can find information on rules, upcoming tournaments,
    tournament results and observer reports, and player rankings.
    UKMA: http://ukmahjong.co.uk/
    This is the official webpage of the UK Mahjong Association. You
    can find information on the UK Riichi Open tournaments and the
    affiliated clubs, among other things.
    Index
    1-away (1-shanten), 52
    golden 1-away, 118, 185
    perfect 1-away, 62, 66, 113, 124,
    126, 192, 213
    side & side 1-away, 126
    2-away (2-shanten), 52
    perfect 2-away, 62
    3-away (3-shanten), 52
    Arcturus, vii
    Barr, Jenn, iv, 260, 261
    blockade (kabe; wall), 198
    bulging float (nakabukure), 72
    chiitoitsu (Seven Pairs), 134, 150,
    172
    chow (shuntsu; run), 52
    dama, 176, 188, 193
    double closed (ryankan) shape, 66,
    114
    EMA, iii, 24, 32, 35, 48, 216, 235, 263
    fanpai (yakuhai; value tiles), 51
    five-block method, 85
    fu (minipoint), 50, 77, 143, 153
    Fukuchi, Makoto, v, 84
    genbutsu, 180, 188
    group (mentsu), 52
    honitsu (Half Flush), 128, 222
    honor tiles (jihai), 51
    insta-riichi, 166, 188
    ittsu, 120, 171
    jihai (honor tiles), 51
    kabe (blockade; wall), 198
    kan (kong), 52, 225
    kantsu (quad), 52, 225
    Katayama, Masayuki, v
    kotsu (set; pung), 52
    mentsu (group), 52
    minipoint (fu), 50, 77, 143, 153
    nakabukure (bulging float), 72
    nobetan (stretched single) shape, 70,
    115
    oka, 23, 32
    Osamuko, viii, 197, 262
    otakaze (valueless wind), 51
    how to discard, 234
    pair (toitsu), 58
    pinfu, 125, 149, 152, 166
    protorun (taatsu), 55
    pung (kotsu; set), 52
    quad (kantsu), 52, 225
    ready (tenpai), 52
    264
    INDEX 265
    run (shuntsu; chow), 52
    ryankan (double closed) shape, 66,
    114
    sanshoku, 111, 167, 168, 170, 185, 227
    set (kotsu; pung), 52
    shuntsu (run; chow), 52
    simple tiles (tanyao hai), 50
    skipping shape, 74
    stretched single (nobetan) shape, 70,
    115
    suji, 195, 215
    suji trap, 173, 175, 179, 182, 186,
    196
    taatsu (protorun), 55
    tanyao hai (simple tiles), 50
    tenpai (ready), 52
    terminal tiles, 50
    tile acceptance (ukeire), 52
    toitoi (All Pungs), 134
    toitsu (pair), 58
    ukeire (tile acceptance), 52
    UKMA, 263
    uma, 23
    value tiles (fanpai; yakuhai), 51
    valueless wind (otakaze), 51
    how to discard, 234
    waits, 76, 176
    closed wait, 55, 76, 177
    dual pon wait, 76, 177
    edge wait, 55, 76, 177
    semi side wait, 76, 177
    side wait, 55, 76, 177
    single wait, 76, 177
    stretched single wait, 76, 177
    yakuhai (fanpai; value tiles), 51

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