San Ankou
三暗刻 | San Ankou
The hand contains three concealed triplets (formed without calling pon).
By Kenji Tanaka · Updated
Overview
San ankou, three concealed triplets, is a 2-han yaku earned when your hand contains three triplets that were each formed without calling, completed from your own draws rather than by pon. The fourth set may be a sequence or an open meld, and the hand need not be fully closed overall, but the three scoring triplets themselves must be concealed. A key subtlety is that a triplet completed by ron counts as open for this yaku, so to count a triplet as concealed you generally must draw its third tile yourself. San ankou sits one step below the yakuman suuankou (four concealed triplets) and combines strongly with toitoi, sanshoku doukou, and yakuhai, with the concealed triplets adding substantial fu on top. Because it depends on self-drawing triplets, san ankou rewards a pair-rich hand played for tsumo, and recognizing when three concealed triplets are within reach can turn a modest hand into a large one.
Example Hand
111m 333p 999s 67m 55z
Conditions
- The hand must contain three triplets (or quads) that were all formed without calling pon; they must be concealed (drawn naturally)
- The fourth meld can be anything (open or closed, sequence or triplet)
- The pair can be completed by any means
- If you win by ron on a tile that completes your third triplet, that triplet is considered open, so only two would be concealed; you need to win by tsumo in that case or have the ron tile complete a different part of the hand
- Worth 2 han regardless of whether the overall hand is open or closed
Strategy Tips
- San ankou is often completed unintentionally when you draw well. If you find yourself with two concealed triplets, be aware that completing a third by tsumo would give you this yaku.
- Pay close attention to how you win. If your tenpai has a shanpon (dual pair) wait, winning by ron means the called triplet counts as open. Winning by tsumo ensures all three triplets remain concealed.
- San ankou can combine with toitoi for a strong hand. If you already have three concealed triplets and a fourth open triplet, you have both san ankou and toitoi for at least 4 han.