Riichi Mahjong basics

Objective of the game

A game of Riichi Mahjong is played over a series of hands. During each hand, every player tries to complete a valid winning hand before their opponents.

Each player normally holds 13 tiles. On their turn, they draw one tile and then discard one tile, gradually improving the structure of their hand. A standard winning hand is made from four groups and one pair, using 14 tiles in total.

Completing this structure is not enough by itself. The hand must also contain at least one Yaku, which is a recognised scoring condition. Yaku and point calculation are explained later in this guide.

Winning hands award points. At the end of the game, the player with the most points wins.

The tiles

Riichi Mahjong uses 34 different tile types. There are four identical copies of every type, producing a complete set of 136 tiles.

The tiles are divided into three numbered suits and seven honour tiles. Each numbered suit contains tiles numbered from 1 through 9.

Manzu

Character tiles numbered from 1 to 9

Pinzu

Circle tiles numbered from 1 to 9

Souzu

Bamboo tiles numbered from 1 to 9

Honours

The four winds followed by the three dragons

The 1 and 9 of each numbered suit are called terminal tiles. Tiles numbered from 2 through 8 are called simple tiles. The winds and dragons are collectively called honour tiles and cannot form sequences.

Some Riichi Mahjong sets replace one or more regular five tiles with red bonus tiles. Riichi Reveal follows a ruleset without these red fives.

Structure of a complete hand

Before looking at complete hands, it helps to understand the smaller combinations from which they are built.

Sequence

Three consecutive tiles from the same numbered suit

Triplet

Three identical tiles

Kan

Four identical tiles that count as one group

Pair

Two identical tiles

Sequence

A sequence contains three consecutive tiles from the same numbered suit, such as 2–3–4 of Manzu. Sequences cannot mix suits, contain honour tiles, or wrap from 9 back to 1. For example, 8–9–1 is not a sequence.

Triplet

A triplet contains three identical tiles. Any numbered tile, wind, or dragon can form a triplet.

Kan

A Kan contains all four copies of the same tile. Although it physically contains four tiles, it counts as one group in a complete hand. A Kan must be declared during play, and the player draws a replacement tile afterward.

Pair

A pair contains two identical tiles. A standard hand requires exactly one pair alongside its four groups.

Standard hand

Four groups + one pair

The groups may be any combination of sequences, triplets, and Kans. This is the most common hand structure.

Sequence

Sequence

Triplet

Triplet

Pair

How a turn works

Most of a Mahjong hand follows a simple cycle: draw one tile, consider the available actions, and discard one tile. Players take turns in counter-clockwise order.

1 Draw2 Check3 Discard4 Continue

Step 1 of 4

Draw a tile

Drawn: 7 Pinzu

The player draws 7 Pinzu from the wall, temporarily bringing the hand to 14 tiles.

Your hand 14 tiles

Discard

Empty

Next South

How a hand ends

A hand normally ends when a player wins by Ron or Tsumo. If the drawable tiles run out before anyone wins, the hand ends in an exhaustive draw.

Open and concealed hands

Every hand starts concealed. It stays concealed while all of its groups are kept hidden from the other players.

Opening a hand does not automatically give it a Yaku. Before calling a tile, check that the finished hand will still contain at least one Yaku that is allowed in an open hand.

Tenpai, waits and winning

Tenpai

A hand is in Tenpai when it is one tile away from a complete hand. The tiles that can complete it are called its winning tiles, or its wait.

Being in Tenpai does not guarantee that the hand may win. The completed hand still needs at least one Yaku.

Common wait shapes

The incomplete part of a standard hand can produce five common wait shapes. The wait shape can affect both Yaku and Fu.

Two-sided wait

Ryanmen

→

Either end completes the sequence: 2–3–4 or 3–4–5.

Closed wait

Kanchan

→

The missing middle tile completes the sequence.

Edge wait

Penchan

→

The only possible tile completes a sequence at the edge of a suit.

Double-pair wait

Shanpon

→

Either tile completes one triplet and leaves the other two tiles as the pair.

Single-tile wait

Tanki

→

One matching tile is needed to complete the pair.

Winning by Tsumo or Ron

The winning tile must complete a valid hand structure and the finished hand must contain at least one Yaku. Which group the winning tile completes can also change the detected Yaku and Fu, so the calculator asks you to identify it.

Riichi and other conditions

Declaring Riichi

Riichi is a Yaku that a player may declare with a concealed hand in Tenpai and at least 1,000 points. The player announces Riichi, places the declaration discard sideways, and pays a 1,000-point stick to the table.

After declaring Riichi, the hand is normally locked: future drawn tiles must be discarded unless the player wins or may legally declare a Kan. The winner of the hand collects the Riichi sticks on the table.

Seat and round winds

Each player has a seat wind; the East-seat player is the dealer. The round wind is shared by all players. A triplet or Kan of your seat wind or the round wind is a Yakuhai. If both winds are the same, the group can fulfil both Yaku.

Special winning events

First-turn wins

Tenhou

The dealer wins with the tiles in their initial hand.

Chiihou

A non-dealer wins on their first self-drawn tile before a call interrupts play.

Renhou

A non-dealer wins by Ron before their first draw and before a call interrupts play.

Scoring basics

Yaku

A scoring condition that makes the hand eligible to win.

Han

The primary value contributed by Yaku and Dora.

Fu

Minipoints awarded for the hand structure, sets, wait, and winning method.

Dora

Bonus tiles that add Han. Dora are not Yaku and cannot make an otherwise Yaku-less hand legal.