Chankan
搶槓 | chankan
Win by claiming the tile another player uses to upgrade an open triplet into a kan.
By Kenji Tanaka · Updated
Overview
Chankan, robbing a kan, is a rare 1-han yaku worth 1 han whether your hand is open or closed. You win it by calling ron on the tile an opponent adds to an existing open pon to upgrade it into a kan (a shouminkan), claiming that tile the instant it is added even though it was not a normal discard. It applies only to added kans: you cannot rob a concealed ankan (except, under common rules, to complete kokushi musou) or an open daiminkan. Chankan cannot be planned, since it depends on an opponent extending a pon with exactly your winning tile while you are tenpai for it, and like any ron it is blocked by furiten. It stacks with your other yaku and combines naturally with rinshan-related play. For the player adding the kan, the risk of being robbed is a reason to be cautious about upgrading a pon late in a dangerous hand.
Example Hand
2m 3m 4m 6m 7m 8m 9p 9p 9p 3s 4s 5s 7p 7p
Conditions
- Another player must attempt to add a fourth tile to an existing open triplet (shouminkan / added kan) — this is sometimes called “upgrading a pon to a kan”
- The tile they are adding must be the tile you need to complete your winning hand
- You call ron on that tile, intercepting the kan before it is completed
- This only works against shouminkan (added kan) — you generally cannot chankan against a closed kan (ankan) or an open kan declared from a discard (daiminkan)
- Exception: Under some rule sets, you can chankan a closed kan if it would complete kokushi musou (thirteen orphans), but this is a rare edge case
Strategy Tips
- Chankan is one of the rarest yaku in the game. You cannot plan for it — it happens when an opponent tries to extend a pon into a kan using exactly the tile you need. When it happens to you, it feels like stealing a win out of thin air.
- Be aware of chankan as a risk when you’re the one making a shouminkan. If you’re adding a tile to an open triplet, that tile is briefly “exposed” and can be claimed by any tenpai player. In a dangerous late game, think twice before upgrading your melds.
- While you can’t aim for chankan, knowing it exists helps with defense. If an opponent is tenpai and you’re about to extend a pon, consider whether the tile you’re adding could be their winning tile. Sometimes it’s safer to skip the kan.