The rarest yaku and fan on Mahjongo
In the period May 2026 – October 2026, we counted 411,235 Riichi hands and 621,591 Chinese Official Mahjong hands in rooms against bots. Every hand with at least one human player is included, so the counts also include hands won by bots.
Riichi
The ten rarest yaku that did appear, rarest first:
Achieve Tenpai with a 9-sided wait for pure nine gates, and win on any one of the nine Number Tiles in the same suit.
Achieve Tenpai with a 13-sided wait for thirteen orphans, and win any one of the thirteen tiles.
Win as the dealer (East player) on your initial self-drawn tile in the first turn.
Win with a hand containing only green tiles, i.e., 2-Sou, 3-Sou, 4-Sou,6-Sou,8-Sou and/or Green Dragons.
Achieve Tenpai with a single-wait for four concealed pungs, and win on a tile that forms a pair in your hand.Win by Tsumo as a non-dealer (not East player) on the self-drawn tile in the first uninterrupted turn (no player calls chow, Pung, or Kong).You'll achieve Mangan when the game ends in a draw, with all your discarded tiles being Terminals and/or Honors, and no player has called them.Win with a hand containing three Triplets or Quads of Wind Tiles and a pair of the fourth Wind Tiles.Win with a hand containing only Terminal Tiles, i.e., 1-Man, 9-Man, 1-Pin, 9-Pin, 1-Sou and/or 9-Sou.Win with a hand containing only Honor Tiles.Not seen at all in this period: Four Big Winds, Four Quads, Nine Gates.
Thirteen Orphans is the yakuman you are most likely to meet. It scored in 337 hands, about once every 1,220 hands. Counting every kind of yakuman together, one came up once every 935 hands.
Chinese Official Mahjong
The ten rarest fan that did appear, rarest first:
Seven consecutive pairs in one suit; Full Flush, Fully Concealed Hand, and Single Wait do not score.
Two 123 chows and two 789 chows in one suit with a pair of 5s; Full Flush, Seven Pairs, and All Chows do not score.
The pattern 1112345678999 in one suit, winning on any additional tile of that suit; Full Flush does not score.
Four kongs plus the pair; Kong and All Pungs do not score, while Prevailing Wind, Seat Wind, Dragon Pung, and Terminal or Honor Pung may still score.
Four wind pungs; kongs count. Prevailing Wind, Seat Wind, Big Three Winds, and All Pungs do not score.
A winning hand consisting of triplets of 1 and 9 suited tiles. Not counted with All Triplets, Double Identical Triplets, or No Honors.
A winning hand made of sequences, triplets and a pair composed of any tiles among 2, 3, 4, 6, 8 of bamboos and Green Dragon (Fa). Half flush is not counted. If the winning hand contains no Green Dragon (Fa), Full Flush can be counted.Three wind pungs plus the fourth wind as the pair; Prevailing Wind and Seat Wind may still score, but Big Three Winds does not.
Two suits each contain 123 and 789, and the third suit's 5 forms the pair; Mixed Double Chow, Two Terminal Chows, No Honors, and All Chows do not score.
Four pungs in one suit, each shifted up one rank; kongs count. Pure Shifted Pungs and All Pungs do not additionally score.Not seen at all in this period: Quadruple Chow.
An 88-fan hand came up once every 1,727 hands. All Green shows how differently the two games play: it scored 17 times in Chinese Official Mahjong and 1 times in Riichi.
How these numbers are counted
A winning hand with several yaku or fan counts once for each of them. All hands come from rooms against bots, so the rates can differ from games between people. The full tables are on the Riichi yaku statistics and Chinese Mahjong fan statistics pages, and every yaku and fan is explained in the Riichi yaku list and the Chinese Mahjong fan list.