What are what wins in Mahjong (Riichi)?

Verdict

A complete hand is four sets and a pair. A set is a sequence, triplet or quad (3.2); A sequence is three consecutive tiles of the same suit — never dragons or winds, and it does not wrap: 8-9-1 and 9-1-2 are not sequences (3.2); A triplet is three identical tiles, a quad four, a pair two (3.2)

Why people argue about this

People often assume that sequences can wrap around the ends of suits (like 9-1-2 for a sequence of Hei tiles), which is incorrect according to the official rules. The confusion arises because they misinterpret the rule stating "A sequence is three consecutive tiles of the same suit — never dragons or winds, and it does not wrap.

Send this to your friend — argument over.

4. Gameplay

Structure of a Game

A full game is two rounds — the east round and the south round — each of at least four hands, during which each player is East in turn (3.1)
A hand ends when a player declares a win or an exhaustive draw occurs (3.1, 3.4)
A turn begins when a player draws from the wall or claims a set, and ends when they discard (3.1)

What Wins

A complete hand is four sets and a pair. A set is a sequence, triplet or quad (3.2)
A sequence is three consecutive tiles of the same suit — never dragons or winds, and it does not wrap: 8-9-1 and 9-1-2 are not sequences (3.2)
A triplet is three identical tiles, a quad four, a pair two (3.2)
A winning hand must be complete and hold at least one yaku (scoring pattern) (3.2, 4.2)
Seven Pairs and Thirteen Orphans are complete despite not being four sets and a pair (3.2)

Turn Order

East begins and play proceeds counter-clockwise. East does not draw on their first turn, having started with fourteen tiles (3.3)
Touching the wall to draw removes a player's right to call the previous discard (3.3)

Riichi

A player with a concealed tenpai hand may declare riichi in three steps: clearly call "riichi", discard a tile rotated sideways, and place a 1,000-point stick as the riichi bet (3.3.10)
Riichi may be declared only if at least one tile remains in the wall (3.3.10)
After declaring, drawn tiles must not touch the hand — they are placed apart or discarded immediately (3.3.10)
A riichi declarer who wins reveals the tiles beneath the dora indicators as ura dora, usable only by players who declared riichi (3.3.10)
The declarer recovers their bet by winning; otherwise the winner collects it (3.3.10)

Declaring a Win

Tsumo — winning on the tile just drawn, by clearly calling "tsumo". A furiten player may still call tsumo (3.3.11)
Ron — winning on the most recently discarded tile, by clearly calling "ron", unless furiten (3.3.12)
Robbing a quad — the tile added to an extended quad may be claimed for a win with "ron", treated as a win by discard, with the quad declarer paying (3.3.13)
A player is furiten if they have discarded any tile they are waiting on, and may not then win by discard (3.3.9)
Declaring a win by self-draw after discarding a tile is invalid (6.8)
"Mahjong" is not a valid win declaration under the 2025 rules (6.5.3)

4. Gameplay

Structure of a Game

A full game is two rounds — the east round and the south round — each of at least four hands, during which each player is East in turn (3.1)

A hand ends when a player declares a win or an exhaustive draw occurs (3.1, 3.4)

A turn begins when a player draws from the wall or claims a set, and ends when they discard (3.1)

What Wins

A complete hand is four sets and a pair. A set is a sequence, triplet or quad (3.2)

A sequence is three consecutive tiles of the same suit — never dragons or winds, and it does not wrap: 8-9-1 and 9-1-2 are not sequences (3.2)

A triplet is three identical tiles, a quad four, a pair two (3.2)

A winning hand must be complete and hold at least one yaku (scoring pattern) (3.2, 4.2)

Seven Pairs and Thirteen Orphans are complete despite not being four sets and a pair (3.2)

Turn Order

East begins and play proceeds counter-clockwise. East does not draw on their first turn, having started with fourteen tiles (3.3)

Touching the wall to draw removes a player's right to call the previous discard (3.3)

Riichi

A player with a concealed tenpai hand may declare riichi in three steps: clearly call "riichi", discard a tile rotated sideways, and place a 1,000-point stick as the riichi bet (3.3.10)

Riichi may be declared only if at least one tile remains in the wall (3.3.10)

After declaring, drawn tiles must not touch the hand — they are placed apart or discarded immediately (3.3.10)

A riichi declarer who wins reveals the tiles beneath the dora indicators as ura dora, usable only by players who declared riichi (3.3.10)

The declarer recovers their bet by winning; otherwise the winner collects it (3.3.10)

Declaring a Win

Tsumo — winning on the tile just drawn, by clearly calling "tsumo". A furiten player may still call tsumo (3.3.11)

Ron — winning on the most recently discarded tile, by clearly calling "ron", unless furiten (3.3.12)

Robbing a quad — the tile added to an extended quad may be claimed for a win with "ron", treated as a win by discard, with the quad declarer paying (3.3.13)

A player is furiten if they have discarded any tile they are waiting on, and may not then win by discard (3.3.9)

Declaring a win by self-draw after discarding a tile is invalid (6.8)

"Mahjong" is not a valid win declaration under the 2025 rules (6.5.3)

What Wins