Ruleset

Agari plays standard four-player riichi mahjong. This is the full ruleset: yaku, scoring, fu, calls, and how a match runs from deal to game end.

Match Format

Agari offers two match types: tonpuusen (East only), a single East round, and hanchan, an East round followed by a South round. Both are four players, no flowers or seasons. Everything below applies to both lengths unless noted.

Uma, oka, and leftover riichi-stick redistribution apply to ranked tonpuusen and hanchan matches. The Daily Wall single-round mode uses raw end-of-round scores instead, with no placement bonuses and no stick redistribution.

Tiles

Agari uses the standard 136-tile riichi set: 34 distinct tiles, four of each. There are three number suits: manzu (萬子, characters), pinzu (筒子, circles), and souzu (索子, bamboo), plus the four winds and the three dragons.

Some of the regular fives are replaced by red fives (akadora), and each one in a winning hand counts as an extra dora. The number of red fives is configurable: none, 3 (one per suit), or 4 (one per suit plus a second red five of pinzu). Agari defaults to 3.

Winning a Hand

A hand wins (an agari) when all of the following are true:

1. The hand is complete. The 14 tiles (your 13 plus the winning tile) form one of:
   • four sets plus a pair (the standard shape),
   • seven distinct pairs (chiitoitsu, no duplicate pairs allowed), or
   • kokushi musou (thirteen orphans): one of each terminal and honour, plus a duplicate of any one of them.
2. The hand has at least one yaku. Dora are not a yaku and never let a hand win on their own.
3. You are not in furiten (see Furiten). A furiten hand can still win by tsumo (self-draw).
4. Atozuke is allowed. The yaku only needs to be present at the moment you win; you may win on the very tile that grants it.

Yaku

Every winning hand needs at least one yaku. Values below are shown as closed / open han; a "✗" means the yaku is only possible with a closed hand.

Standard yaku

Situational yaku

These depend on how or when you win rather than the hand's shape.

Yakuman

Yakuman are the limit hands. They stack additively with no cap: a hand that qualifies for more than one is worth their combined total, and each hand marked double yakuman below counts as two. (For example, a hand that is both all honours and all four winds scores tsuuiisou + daisuushii together.) A counted yakuman (kazoe, from 13+ han) always counts as a single yakuman.

Dora

Dora add han to a winning hand but are not a yaku. They can't win a hand on their own.

Indicators cycle: numbers 1→2→…→9→1, winds E→S→W→N→E, dragons haku→hatsu→chun→haku.

Scoring

A win's value comes from its han (from yaku and dora) and its fu (see Fu). Common payments are below; the named limit hands take over for larger hands.

A hand reaches mangan at 5+ han, or 4 han 40+ fu, or 3 han 70+ fu. Kiriage mangan is off, so a 4 han 30 fu hand pays 7,700 / 11,600 rather than a rounded-up mangan. Triple and quadruple yakuman continue the pattern: N times the single-yakuman value.

Honba (repeat counter)

Each honba adds +300 to the winning payment: +100 from each player on a tsumo, or +300 from the discarder on a ron. The counter goes up after every dealer win or exhaustive draw, and resets to zero when a non-dealer wins.

Riichi bets

Declaring riichi places 1,000 points on the table. The winner of the hand collects every riichi stick on the table. If the hand ends in an exhaustive draw, the sticks carry over to the next hand. Any sticks left on the table at game end go to first place.

If an opponent rons your riichi tile (the discard you declared on), the riichi never takes effect. Your 1,000 comes back and the winner only takes sticks that were already on the table.

Fu

Every hand starts at 20 fu, then adds the values below. The total is rounded up to the nearest 10.

Sequences, simple pairs, and two-sided (ryanmen) or dual-pair (shanpon) waits add no fu. Three special cases:

• Chiitoitsu is always 25 fu.
• Pinfu by tsumo is always 20 fu.
• Pinfu by ron is 30 fu (20 plus the closed-ron bonus).

Furiten

A player in furiten cannot win by ron, only by tsumo. There are three ways to be in furiten:

Furiten is based on your wait shape, not yaku: any tile that completes your hand triggers furiten (even one that would give you no yaku and couldn't be won on).

Calls

Double ron is on: two players can win on the same discard, and each scores their hand independently. (Triple ron is also a win; see Abortive Draws.) When more than one player rons, the riichi sticks and the honba bonus go to the winner closest to the discarder in turn order.

After a chii or pon you must discard to continue. You can't declare a tsumo or a kan off a hand that happens to be complete after a call; those need an actual draw from the wall.

Riichi

To declare riichi your hand must be closed and in tenpai. You discard sideways and place 1,000 points on the table. After that the hand is locked: you discard each tile as you draw it.

• Ankan after riichi is allowed only if it doesn't change your wait.
• Furiten riichi is allowed. You may declare even while in furiten, but you can then only win by tsumo.
• Winning within one uninterrupted go-around of declaring scores ippatsu; any call in between cancels it.

Kan

• At most four kans per hand across all players. A fifth attempt aborts the hand, unless all four belong to one player going for suukantsu.
• Each kan draws a replacement tile from the dead wall and flips a new dora indicator.
• Dora flip timing: a closed kan flips its indicator immediately; an open or added kan flips after the discard.
• A replacement-tile win scores rinshan kaihou.
• Opponents may ron the tile used for an added kan (chankan). A hand in kokushi tenpai may also rob a closed kan; no other hand can.

Exhaustive Draw

If the wall runs out with no winner, players reveal whether they're in tenpai. Noten players pay 3,000 points total, split among the tenpai players:

The dealer keeps the deal if tenpai and passes it on otherwise; the honba counter goes up either way. If a player meets the nagashi mangan conditions (all their discards are terminals/honours, none called), that pays out as a mangan instead of the tenpai exchange.

Abortive Draws

Some situations end the hand immediately with no score change. The hand is redealt, honba goes up, and the dealer keeps the deal.

Triple ron is not an abortive draw in Agari; all three winners score their hands independently.

Game End

After the final round (South 4 in a hanchan, East 4 in a tonpuusen, or the last extra hand), placement is decided by score. The game can also end early:

Ties are broken by seating order: the seat closer to the starting dealer ranks higher.

Pao (Liability)

If a player's called tile directly completes an opponent's daisangen (third dragon triplet) or daisuushii (fourth wind triplet), that player becomes liable for the yakuman:

• On a tsumo, the liable player pays the entire yakuman alone.
• On a ron by someone else, the discarder and the liable player split the payment in half.