4-Player Riichi Mahjong:
Rules & How to Play

Guide to 4-Player Mahjong

Four-player Riichi is the standard Mahjong game, the format played in pro leagues across Japan.

CoinMahjong uses full Japanese rules: red fives, dora and ura dora, and full han and fu scoring.

This guide covers everything you need for your first table.

Game Formats

It’s important to use approach each Mahjong format differently.

The dealer keeps the deal after a dealer win or a drawn hand where they’re tenpai. Each repeat-hand counter (honba) adds 300 points to the next win.

The Tiles

A 4-player set has 136 tiles: three numbered suits and seven honor tiles, with four copies of each.

• Man (characters), Pin (circles) and Sou (bamboo): each numbered 1 to 9.
  The 1s and 9s are called terminals, and 2 to 8 are simples.
• Winds: East, South, West and North.
• Dragons: white (Haku), green (Hatsu) and red (Chun).

There are four red fives: one 5 characters, one 5 bamboo, two 5 circles.

Red fives count as dora, bonus tiles that add 1 han each to a winning hand.

Building a Winning Hand

A winning hand has 14 tiles: four sets and a pair (the jantou). The hand must also include at least one yaku.

There are three kinds of set:

• Sequence (shuntsu): three consecutive numbered tiles in one suit, such as 3-4-5 of circles.
• Triplet (koutsu): three identical tiles, such as three East winds.
• Quad (kantsu): four identical tiles, declared as a kan. You draw a replacement tile, so a quad still counts as one set.

One special hand breaks the four-sets-and-a-pair shape: seven pairs (chiitoitsu), covered in the Hands and Scoring guide.

You win by drawing your winning tile from the wall (tsumo) or claiming another player’s discard (ron).

You can’t win by ron on a tile you’ve already discarded, but you can still win by tsumo.

Calling Tiles

You can claim another player’s discard to complete a set.

Calling speeds up your hand but usually opens it.

If two players can win on the same discard, the next player after the discarder wins.

Declaring Riichi

You can declare Riichi when your hand is closed and one tile from winning (tenpai).

To declare, you stake 1,000 points and turn your discard sideways. You also need at least 4 tiles left to draw.

A ron on the riichi discard cancels the riichi and returns the 1,000.

From then on your hand is locked: you draw and discard until your winning tile arrives.

Riichi adds 1 han and reveals ura dora if you win, which can push a cheap hand into a big one.

The cost is flexibility, and every opponent now knows to play defensively.

Rules in Effect

Before anything advanced, learn the basics.