A description of the rules of Japanese mahjong is provided. The appendix provides a list of yaku and recommendations on how to start playing riichi mahjong and how to become stronger. Here's a short description of R Mahjong - a riichi mahjong app with strong mahjong AI.

1. JAPANESE RIICHI MAHJONG RULES
Version 0.9

2. 2

3. 3
GAME SET
Riichi Mahjong is played with 136 tiles. There are three suits from 1 to 9: man, pin, sou:
Man:
Pin:
Sou:
There are also four winds: east, south, west, north.
East South West North
And there are three dragons: white (haku), green (hatsu), red (chun).
White Green Red
There are 4 pieces of each tile. A round indicator and 2 d6 dice are also used.
Among the suits there are terminal tiles (1s and 9s) and averages (from 2 to 8). Winds and dragons are noble
tiles.
PREPARATION FOR THE GAME
Each game (hanchan) in riichi mahjong consists of two rounds: eastern and southern. Each round lasts a
minimum of 4 hands (each player must be the dealer in each round). For seating at the table, tiles of the four
winds are taken, placed face down, and mixed. Players choose one tile at a time and sit according to the drawn
winds. To the right of the East sits the South, opposite is the West, and to the left is the North. The player who
drew East is appointed as the permanent dealer. He takes the round indicator and places it to his right.
The tiles are thoroughly mixed. Each player builds a wall of face-down tiles in front of him, seventeen tiles
in length, two in height. The four walls are pushed together to form a square:
The current dealer (East) rolls 2 dice and determines where the wall will break. He counts this number by
players counterclockwise, starting with yourself. The player determined in this way counts the number of pairs
of tiles on his wall from right to left according to the sum of the numbers on the dice and pushes the tiles apart,
making a gap. This player to the right of the gap counts out 7 pairs of tiles and makes another gap. The selected
14 tiles form a dead wall. The dead wall continues after the corner, onto the next wall if the end of the wall is
reached.

4. 4
In the dead wall, the third tile from left to right turns over - this is a dora indicator. The 4 tiles to the left of
the dora indicator are replacement tiles:
The East player takes the first four tiles after the initial break in the wall. Tiles are taken clockwise, while
players turn counterclockwise: South takes the next four tiles, West takes the next four, North takes the next
four, and so on until all players have twelve tiles. East then takes 2 tiles: the top tiles from the first and third pile
in the wall. South, West and North each take one tile in order. East now has a starting hand of fourteen tiles,
while the other players have thirteen tiles.
The East player takes the first four tiles after the initial break in the wall. Tiles are taken clockwise, while
players turn counterclockwise: South takes the next four tiles, West takes the next four, North takes the next
four, and so on until all players have twelve tiles. East then takes 2 tiles: the top tiles from the first and third pile
in the wall. South, West and North each take one tile in order. East now has a starting hand of fourteen tiles,
while the other players have thirteen tiles.
GAME FLOW
East starts the hand. He discards 1 of 14 tiles from his hand. South (the player to the right of East) moves
next. He takes a tile from the end of the wall into his hand and demolishes any tile from his hand into the discard.
Next, players continue to take turns going counterclockwise.
Each player forms their own discard by laying down discarded tiles in front of them 6 in a row.

5. 5
A player’s turn begins with taking a tile and ends with discarding a tile. During one circle, all players make
one move.The circle is interrupted if the tile is claimed for kan, pon or chi. The hand lasts until either player
completes the hand and wins, or there is a draw. In one round, all players take turns being East. A full game
consists of two rounds: the east round and the south round.
After the end of the hand, if East did not win or did not have a ready hand (tenpai) in a draw, the winds
change. The next (counterclockwise) player becomes East (the next current dealer).
GAME OBJECTIVE
The goal of the game is to collect a completed hand. The ultimate goal of the game is to score as many points
as possible from the hands you win. At the beginning of the game, each player receives 25,000 points. Points
do not appear or disappear, but are redistributed between players. If someone loses all their points, then the
hanchan ends early.
The main way to get points is to win individual hands. To do this, you need to collect 4 sets and a pair in
your hand.
Sets are any 3 identical tiles (koutsu), 3 consecutive tiles of the same suit (shuntsu), any 4 identical tiles
(kantsu):
shuntsu
koutsu
kantsu
In riichi there are two special hands that do not consist of four hands and a pair: Seven pairs (chitoitsu) and
thirteen orphans (kokushi muso).
A hand of 13 tiles that is missing the last tile to be complete is called a completed hand (tenpai). The tiles
on which a player can declare victory are called winning tiles. If the winning tile is obtained on your turn by
taking from the wall, the victory is declared with the word "tsumo", if the winning tile was discarded by another
player, then with the word "ron".
After declaring victory, the player opens his hand, shows the winning combination, calculates its value and
names the payout amount. A tile taken by tsumo is not built into the hand; it is placed separately so that others
can see it. Then the rest of the hand is opened.

6. 6
ANNOUNCEMENT
The last of the discarded tiles can be claimed by any of the other players, provided that they are able to
complete the mahjong hand, declare kan or pon. If a player has a pair of tiles of the same suit in order, and the
opponent on the left discards a tile that fits in that row, then the player can declare Chi.
In this case, the player opens 2 of his tiles and completes the open set by taking the missing tile from the
opponents discard. The taken tile is placed horizontally in the set on the left:
If a player has a pair of identical tiles, and any other opponent discards the same tile into his discard, the
player may say "Pon!", open 2 of his tiles, and complete the open set by taking the missing tile from his oppo-
nent’s discard. The taken tile is placed horizontally in the set on the right, left or middle, depending on which
opponents discard it was taken from:
If a player has three identical tiles in his hand, and any other player discards a fourth identical tile to the
discard, then the player can declare a Kan (open Kan) on this discard. The tile taken from another player’s
discard to complete the kan is placed horizontally, as is the case with open pon and chi:
In addition to the open can, there is also an added can and a closed can.
The added kan can be declared by the player who previously declared the pon if he takes the 4th same tile
from the wall. The tile is placed on top of a tile lying horizontally.
If a player has 4 identical tiles in his hand, he can declare a closed kan at any time on his turn, after taking
a tile from the wall. 4 identical tiles in a closed hand are not a kan, to get a kan it must be declared. The player
announces the kan, lays out 4 tiles and shows them to the others. Then flips over the outer 2 tiles:
After the kan is announced, the player takes a replacement tile from the dead wall, the leftmost one. After
taking a replacement tile, the player discards any tile from his hand to the discard. After the kan is announced,
the player opens a kan-dora indicator to the right of the dora indicator. There can be a maximum of 4 kan in the
game. If they are not declared by one player, then the hand ends in a draw.
In the course of the game, there should always be 14 tiles in the dead wall. After the kan is declared, the
last tile of the living wall is added to the dead wall. Collected open sets are placed to the right of the hand
sequentially from bottom to top.
Claiming a tile to win takes precedence over any other claim. Claiming a tile for kan or pon takes precedence
over claiming a tile for chi.
YAKU PRINCIPLE
In riichi mahjong, in order for a finished hand (tenpai) to win, it must have at least one yaku. Yaku are special
combinations of tiles in your hand. Each yaku has a cost in han.
Yaku can be combined with each other and mutually exclusive. If yaku are combined, then if they are present
at the same time, when calculating the value of the hand, the hans for them are added up. A list of yaku, their
cost in han and a table of their compatibility are given at the end of the document.
Yaku can be closed or open. The concept of "open" and "closed" in this case refers to tenpai. For both open and
closed hand, victory is possible in both ron and tsumo. An open tenpai is a tenpai that has open sets collected
during the game (during one hand). A player may have a situation where the hand is tenpai, but there is no
yaku in it.
DORA
Regular Dora
Dora is a tile that adds 1 han to the hand value, but does not give yaku. The tile that will be the dora is
determined in the hand when the dora indicator on the dead wall is opened. The dora indicator points to the
next tile in order, which will be the dora. For example, the 2 pin indicator indicates that the dora will be the 3
pin. 9 sou indicates that the dora will be the 1 sou.
The order of the winds when determining the dora East-South-West-North-East, the order of the dragons is
White - Green - Red.

7. 7
Aka Dora
Aka dora are red fives. They replace the usual fives. Typically three red fives are used, one in each suit:
Kan Dora
Kan Dora appear after the announcement of the Kan and the opening of a new indicator.
Ura Dora
Ura Dora are additional dora that are opened for the player who declares riichi and wins. The Ura Dora
indicators are located under the dora and open Kan Dora indicators. The player takes them into account when
counting.
RIICHI
If there is a tenpai in a fully closed hand, then riichi can be called. Riichi is a yaku worth 1 han. Herewith:
• You need to deposit 1000 points. They will be taken by the one who wins the hand first (not this one, if
there is a draw, then the next one). If a player does not have 1000 points, he cannot declare riichi.
• Once riichi is declared, you cannot change your hand. Tiles taken from the wall are not added to the hand;
all unsuitable tiles are discarded. Declaring a closed kan is possible as long as it does not change the existing
expectations in the hand.
• A player who, after declaring riichi, decides not to win from the discarded tile ending his hand becomes
furiten, and cannot win by ron for the rest of the hand. He can still win by tsumo.

8. 8
• If a player with riichi wins, ura-dora indicators open for him:
• When announcing riichi, the player says "riichi", discards the tile into the discard on his turn and places
it horizontally. The player places a 1000 point stick in front of his discard. If one of the opponents took
this discarded tile for a set, then the player on the next discard places the tile horizontally. If a victory was
declared on the tile that was discarded when riichi was announced, then 1000 points are returned to the
player. Riichi is considered undeclared.
FURITEN RULE
This rule prohibits a player from declaring a victory by ron if he has a tile in his discard that ends the winning
wait. In this case, victory by tsumo can be declared. A player who is a furiten may decide to change his hand to
no longer be a furiten (unless he has declared riichi).
If one of the players discards a tile that ends the winning wait for the second, and the second does not declare
victory on this discard, then he is in furiten (temporary furiten) until his next tile is taken from the wall (that
is, he cannot declare victory by ron). If the circle was interrupted by the announcement of kan, pon or chi, the
player is no longer furiten.
The temporary furiten state is terminated whenever the player picks up a tile from the wall, i.e. the player is
never considered furiten when taking a tile from the wall. If a player declares riichi and misses the win by ron,
he is in furiten until the end of the hand and can only win by tsumo.
DECLARING VICTORY
When a hand ends with one or more players declaring victory, the value of the hand(s) is counted. Only
the winners receive payments. The player who wins by taking a tile from the wall receives payment from three
opponents. A player whose discard results in one or more victory declarations pays the full value of the hand
to each winner.
East gets more points for a win, but also pays more if the opponent wins by taking a tile from the wall. When
East wins a hand (regardless of whether the players are still winning or not), a counter is placed on the table to
the right of East.
EXHAUSTIVE DRAW
An exhaustive draw occurs when no one declares victory after the last tile is discarded. Fourteen dead wall
tiles are not used. In an exhaustive draw, the noten players (player who cannot or will not show a tenpai hand)
pay a penalty to the tenpai (waiting) players (players who show a tenpai (waiting) hand). The total penalty for
a noten is 3000 points.
For example, if three players are tenpai, the noten player pays 1000 points each, but if one player is tenpai,
he receives 1000 points from each noten player.
In the event of an exhaustive draw, the players who declared riichi are required to demonstrate their tenpai
hands. After an exhaustive draw, a counter is placed on the table to the right of East.
ABORTIVE DRAW
After an abortive draw, no penalty is paid for the noten, and players who call riichi are not required to show
their tenpai hands, unless four riichi are called.
An abortive draw may happen in four cases:
• A player with nine different terminal and noble tiles after his first take from the wall on the first uninter-
rupted circle may declare an abortive draw.
• No one wins after the fourth kan is declared, and these four kans do not belong to the same player.
• All players discard the same wind in the first uninterrupted circle.
• All four players declared riichi, and no one declares victory with the discard of the fourth player.

9. 9
COUNTERS
After a hand in which East has won, or after an exhaustive draw or an abortive draw, one counter is placed
on the table to the right of East. Each counter on the table increases the value of the winning hand by 300 points.
In the case of a tsumo win, the payout is split between the opponents each pays the winner 100 points for
each counter in addition to the regular payout for the hand.
All counters are removed from the table after a player other than East declares a win and East does not
declare.
HAND VALUE
All players start with 25000 points. When a player wins in a single hand, he calculates the value of his hand
in hans: for yaku and for doras (if any). If a hand is worth less than 5 han, then to determine the size of the
win, not only hans, but also fu (minipoints) are counted. To determine the size of the payout for hands worth
1-4 hans, a special table is used. Empty spaces in the table indicate that there are no hands with that value. The
top number is the ron payout, the bottom number is the tsumo payout for the dealer and non-dealer. The dealer
uses a separate table to count points.
Not a Dealer
Han
Fu
20 25 30 40 50 60 70 80 90 100 110
1
1000
(500/300)
1300
(700/400)
1600
(800/400)
2000
(1000/500)
2300
(1200/600)
2600
(1300/700)
2900
(1500/800)
3200
(1600/800)
3600
(1800/900)
2
1300
(700/400)
1600
2000
(1000/500)
2600
(1300/700)
3200
(1600/800)
3900
(2000/1000)
4500
(2300/1200)
5200
(2600/1300)
5800
(2900/1500)
6400
(3200/1600)
7100
(3600/1800)
3
2600
(1300/700)
3200
(1600/800)
3900
(2000/1000)
5200
(2600/1300)
6400
(3200/1600)
7700
(3900/2000)
8000
(4000/2000)
4
5200
(2600/1300)
6400
(3200/1600)
7700
(3900/2000)
8000
(4000/2000)
5 8000 (4000/2000) – mangan
6, 7 12000 (6000/3000) – haneman
8, 9, 10 16000 (8000/4000) – baiman
11, 12 24000 (12000/6000) – sanbaiman
13+ 32000 (16000/8000) – yakuman
Dealer – East
Han
Fu
20 25 30 40 50 60 70 80 90 100 110
1
1500
(500)
2000
(700)
2400
(800)
2900
(1000)
3400
(1200)
3900
(1300)
4400
(1500)
4800
(1600)
5300
(1800)
2
2000
(700)
2400
2900
(1000)
3900
(1300)
4800
(1600)
5800
(2000)
6800
(2300)
7700
(2600)
8700
(2900)
9600
(3200)
10600
(3600)
3
3900
(1300)
4800
(1600)
5800
(2000)
7700
(2600)
9600
(3200)
11600
(3900)
12000
(4000)
4
7700
(2600)
9600
(3200)
11600
(3900)
12000
(4000)
5 12000 (4000) – mangan
6, 7 18000 (6000) – haneman
8, 9, 10 24000 (8000) – baiman
11, 12 36000 (12000) – sanbaiman
13+ 48000 (16000) – yakuman
minipoints open closed
pon (simples) 2 4
pon (honor/terminal) 4 8
kan (simples) 8 16
kan (honor/terminal) 16 32
yakuhai pair 2
open wait 0
closed wait 2
edge wait 2
pair wait 2
win 20
extra points for tsumo win1
2
extra points for ron win with closed hand 10
ron (closed hand) 30
chitoitsu 25
1
An exception to the fu for tsumo is a closed hand that satisfies all other criteria for pinfu. Such a hand does not score 2 fu for tsumo and instead gains the han for pinfu.
The final calculations after hanchan are made using uma (10-20):
1st place = (final points - 25000 + 20000) / 1000
2nd place = (final points - 25000 + 10000) / 1000
3rd place = (final points - 25000 - 10000) / 1000
4th place = (final points - 25000 - 20000) / 1000
The resulting values are rounded upward to whole numbers. In the event of an equal number of final points,
the player sitting closer counterclockwise to the first dealer will receive the higher seat.
APPENDIX A: YAKU LIST

10. 10
List of yaku
Han
Open Closed
Menzenchin tsumohou Winning from the wall with a closed hand. 1
Riichi Deposit 1000 points. Fully closed hand. Prohibition on changing hands. 1
Ippatsu Winning on the first circle after riichi is announced, if no other players
make set announcements during that circle.
+1
Pinfu Also known as "all sequences", this is a hand that does not
gain fu based on composition, other than that of a closed ron.
+ or
1
Iipeikou Hand includes two identical sequences. 1
Haitei raoyue Winning by tsumo on the last wall tile. 1 1
Houtei raoyui Win by ron on discarding the last wall tile. 1 1
Rinshan kaihou Winning on the replacement tile after Kan. 1 1
Chankan Robbing a kan. At the moment of increasing an open pon to kan by an-
other player. To complete kokushi muso - at the moment of announcing
a closed kan.
1 1
Tanyao All simples. A hand composed of only inside (numbers 2-8) tiles.
+ or
1 1
Yakuhai A hand with at least one group of dragon tiles, seat wind, or round
wind tiles. This hand can be valued at 1 han for each group.
1 1
Double riichi Riichi’s announcement on the first circle of dealt. +1
Chantaiyao All tile groups contain at least 1 terminal or honor tile.
+
1 2
Sanshoku doujun Three sequences have the same number across the three different suits.
+
1 2
Ittsu Three distinct tile groups containing 123, 456, 789 of one suit. 1 2
Toitoi All triplets.
+ or
2 2
Sanankou Three closed triplets.
+ or
2 2
Sanshoku doukou The hand includes three groups of triplets with the same number.
+ or
2 2
Sankantsu Three kans.
+
2 2
Chiitoitsu Seven pairs.
+
2
Honroutou All terminals and honors.
+ or
2 2
Shousangen The hand contains two sets of 3 dragon tiles and a pair of the third dragon
tiles.
+ or
2 2
Honitsu This is a single suit hand mixed with some honor tiles.
+
2 3
Junchan taiyao All sets and the pair must contain at least one terminal.
+
2 3
Ryanpeikou This hand consisting of two "iipeikou".
+
3
Chinitsu This hand is composed entirely of tiles from only one of the three suits.
+ or
5 6
Nagashi mangan All the discards are terminals and/or honors. In addition, none of these
discards were called by other players.
5 5
List of yakuman
Kazoe yakuman This is a special class of yakuman, where a hand is composed of 13+ han based on the
combination of above regular yaku and/or dora.

11. 11
Kokushi musou This hand has one of each of the 13 different terminal and honor tiles plus one extra
terminal or honour tile.
+
Suuankou This hand is composed of four groups of closed triplets.
+ by Tsumo or
Daisangen This hand involves the collection of all three tile groups of the dragon tiles.
+
Shousuushii This hand has three groups (triplets or quads) of the wind tiles plus a pair of the fourth
kind.
+
Daisuushii This hand has four groups (triplets or quads) of all four wind tiles.
+
Tsuuiisou This hand consists entirely of honor tiles.
+ or
Chinroutou This hand consists entirely of terminal tiles.
+ or
Ryuuiisou This hand composed entirely of green tiles: 2, 3, 4, 6 and 8 Sou and/or Hatsu.
+ or
Chuuren poutou This hand contains the 13-tile pattern 1-1-1-2-3-4-5-6-7-8-9-9-9 of the same suit, plus any
one more tile from the suit. In addition, the hand must be closed.
+ any pin tile
Suukantsu Any hand with four calls of kan.
+
Tenhou The dealer hand is a winning hand even before discarding a tile.
Chiihou The non-dealer hand is a winning hand with the first tile draw.
APPENDIX B: HOW TO START PLAYING RIICHI MAHJONG? HOW TO BECOME
STRONGER?
If you are a beginner player, then it is better for you to start playing riichi mahjong using such mahjong
applications that allow you to think about the move for a long time. At the same time, in order to become
stronger in mahjong, you need to practice playing against strong opponents. These conflicting requirements are
met by R Mahjong, a next-generation riichi mahjong app. Equipped with strong Mahjong AI based on neural
networks, this application is able to provide you with practice against strong opponents. The training mode
allows you to see your opponents’ hands and receive hints from the AI - which tile to discard, and whether or
not to make an announcement (Chi, Pon, Kan, Riichi).
R Mahjong’s system for collecting and displaying game statistics is second to none. It allows you to analyze
not only the statistics of your games, but also the statistics of your opponents’ games, including AI. Studying the
statistics will help you detect and correct systematic imbalances that may occur in your game in time.

12. 12
In addition to all of the above, R Mahjong allows you to play mahjong with your friends over a local network
(via Wi-Fi). Moreover, you will be able to play mahjong for four people even if you don’t have enough players
- R Mahjong will automatically replace missing players by bots. In multiplayer mode, both strong and weak AI
are available. It should also be noted that R Mahjong is completely free.