Riichi Mahjong · Yakuman

Suukantsu (Four Kans) in Riichi Mahjong: Yakuman Rules and Scoring

In riichi mahjong, Suukantsu (four kans) is a yakuman: one player declares four kans and then wins by completing the pair with the last tile. Closed, open and added kans all count, and it's yakuman even when open. It's often called the rarest yakuman of all: four different tiles, all four copies of each, and in the end only a single wait.

The rules for Suukantsu

• One player declares four kans (closed, open or added — any mix)
• Only one tile is left besides the four kans, so it's always a single wait; pair it and you win
• Tsumo or ron, open or closed — always yakuman
• If the four kans are split between two or more players, it's not suukantsu but a four-kan abortive draw

How Suukantsu is scored

The yaku and points below are computed live by the same scoring code the game uses.

Yakuman ignore fu and han; suukantsu is simply the yakuman payment. If all four kans are closed and you win on the single wait, it's also suuankou on a single wait. Like Mahjong Soul, this site stacks yakuman, so single-wait suuankou (double yakuman) plus suukantsu is a triple yakuman; on Tenhou single-wait suuankou is a single yakuman, so the total is double.

Suukantsu and the four-kan draw

This site follows Tenhou and Mahjong Soul:

• A hand allows four kans. If they belong to two or more players, the hand is aborted (suukaikan) once the discard after the fourth kan passes without a ron.
• If one player made all four, there's no draw: play continues with that player on a single wait for suukantsu. Nobody else can kan any more.
• So with sankantsu in your hand, a fourth kan doesn't abort the hand — it puts you in yakuman tenpai.
• This site has no liability payment (pao) for suukantsu; some rulesets make the player who fed the fourth kan pay.

Why Suukantsu almost never happens

• Four tiles, four copies each: all sixteen must end up in your hand or your calls.
• Every kan is visible and adds dora for everyone; by the third kan the other players are usually defending.
• The last wait is a single tile, with at most three copies left.

In 40,000 hands between four computers at normal level, suukantsu happened 0 times and sankantsu 0 times. If you get one, it's a hand to remember — try your luck at free online riichi mahjong.

Suukantsu in other mahjong styles

• Chinese Official (Guobiao), "Four Kongs": 88 fan (Guobiao fan list)
• Hong Kong mahjong: "Eighteen Arhats", a limit hand (Hong Kong mahjong fan list)

FAQ

Is Suukantsu a yakuman?

Yes. Suukantsu is a yakuman, even with open kans.

Do the kans have to be closed?

No. Closed, open and added kans all count. If all four are closed, it's also suuankou.

When does a fourth kan end the hand in a draw?

Only when the four kans are split between two or more players. If one player has all four, play continues and that player waits for suukantsu.

Related yaku

Sankantsu Closed 2 / open 2 Three kans by one player — 2 han, even open. Rules, big fu, common combos and the four-kan draw. Rinshan kaihou Closed 1 / open 1 Win on the replacement tile after a kan — 1 han, open or closed. Rules, scoring examples, kan dora and how often it happens. Suuankou Yakuman（closed only） Four concealed triplets, closed only — a yakuman. Shanpon needs tsumo, a single wait wins on ron too (double yakuman here), and how many pairs you need.