Suuankou (四暗刻)
Four concealed triplets.
How Suuankou (四暗刻) works
Suuankou (four concealed triplets) is a yakuman hand of four triplets, all of which are formed without calling — entirely concealed — plus a pair.
Each of the four triplets must be completed in hand, not by claiming a discard. Crucially, the winning tile must complete the pair (not a triplet) if you win by ron, otherwise that triplet counts as open and the hand falls short. Winning by tsumo on a triplet's third tile keeps all four concealed and a wait on the pair can produce the suuankou tanki double-yakuman variant.
- •All four triplets must be concealed; calling any of them voids the yakuman.
- •A ron that completes a triplet makes that triplet 'open' and downgrades the hand to toitoi/sanankou.
- •A single-wait on the pair (tanki) is often scored as a double yakuman in many rules.
Suuankou (四暗刻) — FAQ
Why does winning by ron sometimes ruin suuankou?
A triplet completed by ron counts as open rather than concealed. If your win completes a triplet by ron, you only have three concealed triplets and miss the yakuman.
How can I safely win suuankou by ron?
Win by ron only when your wait is on the pair (a tanki/single wait). Then all four triplets stay concealed and the hand counts.