Curriculum · 48 / 50
Kan in detail
Ankan, daiminkan and kakan: learn the three ways to declare a kan in riichi mahjong, the extra dora and fu bonuses, and the chankan trap.
The principle
A kan groups all four copies of the same tile, and there are three ways to declare one. The ankan (closed kan) is laid from four tiles in your own hand on your draw: the four tiles are displayed according to the kan procedure, but your hand keeps its concealed status and can still declare riichi. The daiminkan (open kan) is formed by calling an opponent's discard when you already held three copies, and it opens your hand. The kakan (or shouminkan, added kan) completes a pon you already melded by adding the fourth tile to it.
Rule and example
Every completed kan grants a replacement draw from the dead wall. Under Tenhou, the new indicator appears immediately for ankan, then normally after the discard for daiminkan or shouminkan. WRC 2025 reveals it before the discard for all three types. Winning on the replacement draw scores rinshan kaihou. Kan are worth 8 to 32 fu depending on tile type and openness.
What changes
A kakan can be robbed by chankan before completion; no new indicator then remains. Under both Tenhou and WRC 2025, an ankan cannot be robbed, even by kokushi musou. A completed kan also adds one potential uradora indicator for any riichi winner.
Mistake to avoid
After riichi, an ankan remains possible when the drawn tile completes a triplet already held and the wait does not change. Tenhou allows structure or yaku to change, while WRC 2025 also requires the structure to remain unchanged. Declaring a kan shortens the live wall by one draw and offers everyone another potential dora.
Rules references
- Tenhou rulesReference profile used for game mechanics and scoring.
- WRC Rules 2025International rules compared whenever their options differ from Tenhou.