Suu Ankou

Conditions

• The hand must contain four triplets (or concealed kans), and all four must be concealed (self-drawn, never called via pon)
• The remaining two tiles form the pair
• The hand must be closed — calling pon for any triplet disqualifies the hand entirely
• If you win by ron (claiming a discard), the discard must complete the pair, not a triplet — otherwise the fourth triplet would count as an open meld and suu ankou is invalid
• Winning by tsumo (self-draw) avoids this issue since all tiles were self-drawn
• Some rulesets award double yakuman for a tanki (single tile pair) wait

Strategy Tips

• Suu ankou is essentially toitoi played entirely closed with all four triplets concealed. If you find yourself with three concealed triplets and several pairs, consider whether you can complete the fourth triplet by self-draw rather than opening your hand with pon.
• The safest path to suu ankou is winning by tsumo, because a ron win only works if the winning tile completes your pair (shanpon wait on the pair side). Plan your hand so that your tenpai wait is ideally a single tile for the pair.
• Watch your draw carefully when you have three concealed triplets. It can be tempting to call pon to speed things up, but doing so converts a potential yakuman into a much lower-scoring toitoi or san-ankou hand.