What are Haitei and Houtei? Last-Tile Yaku Explained
Haitei and Houtei are a paired set of 1 han yaku that reward winning on the very last tile of the live wall. One is for self-draw, the other for ron — here is the full picture.
What are Haitei and Houtei?
Haitei Raoyue (海底撈月, "scooping the moon from the seabed") is a 1 han yaku for winning by tsumo on the very last drawn tile from the live wall. Houtei Raoyui (河底撈魚, "scooping a fish from the riverbed") is its companion 1 han yaku for winning by ron on the very last discard of the hand. They are always taught together because they cover the two possible ways a final-tile win can happen.
When exactly is the "last tile"?
The live wall — the tiles players draw from — is the wall minus the 14 reserved dead-wall tiles. Once the live wall is exhausted the hand ends (ryuukyoku). The "last" tile for haitei is the final tsumo before that exhaustion; the "last" tile for houtei is the discard the final tsumo-er throws after taking that draw. If neither wins on either, the hand goes to ryuukyoku and the yaku never trigger.
Haitei vs Houtei — what is the difference?
Haitei requires tsumo on the very last draw — you complete your own hand from the wall. Houtei requires ron on the very last discard — someone else throws your winning tile right at the end. The mechanics are otherwise identical: both are 1 han, both are open-or-closed friendly (no menzen requirement), and only one of them can possibly trigger in any given hand.
Can they stack with other yaku?
Yes — both stack freely with most yaku as long as the hand otherwise qualifies. Common companions are riichi (since the player still needs at least one yaku besides haitei/houtei in many casual circles, and riichi makes most last-tile wins comfortably valid), tanyao, pinfu and dora. They cannot stack with rinshan kaihou (rinshan wins use a dead-wall tile, not the last live-wall tile) or chankan.
How rare are last-tile wins?
Uncommon but not vanishingly rare — about 0.5 to 1 percent of all wins for the pair combined. Most hands finish well before the wall runs out: a typical riichi-mahjong hand resolves within 12-16 turns of a 17-turn wall. When a hand drags to the very last draw, someone is usually tenpai and the final tile has a decent chance of being live, so the conditions line up just often enough to keep the yaku from feeling theoretical.