Yaku guides · 8 / 17
Suuankou: four concealed triplets
Suuankou is a yakuman: four concealed triplets or kans plus a pair. Ron on a shanpon wait breaks it, tsumo and a tanki wait keep it.
The principle
Suuankou (四暗刻) requires four concealed triplets or kans and a pair. An ankan remains concealed and can contribute to the yakuman. Any chi, pon, daiminkan, or kakan opens part of the hand and removes suuankou.
Rule and example
Tsumo naturally keeps the fourth triplet concealed. On ron, the wait decides the result. If the opponent’s tile completes the fourth triplet on shanpon, that group becomes open and suuankou is lost. If all four triplets already exist and ron only completes the pair on tanki, the yakuman remains valid.
What changes
This distinction separates sanankou from a true suuankou. Three concealed triplets already give 2 han through sanankou, even when the rest of the hand is open. The fourth concealed group and the winning method move the hand into a different category.
Mistake to avoid
Some rules award double value to suuankou tanki. Tenhou and WRC 2025 score it as a single yakuman, just like the version won by tsumo. Tenpai.gg follows that profile and does not automatically double the tanki form.
Rules references
- Tenhou rulesReference profile used for game mechanics and scoring.
- WRC Rules 2025International rules compared whenever their options differ from Tenhou.