Riichi Mahjong · Yakuman（closed only）
Suuankou (Four Concealed Triplets) in Riichi Mahjong: Yakuman Rules, Tanki and Odds
In riichi mahjong, Suuankou (four concealed triplets) is a yakuman: all four sets of your winning hand are triplets you drew yourself (concealed triplets), plus a pair. A single pon breaks it, so it is always a closed hand.
On this page
The rules for Suuankou
- All four sets are concealed triplets: self-drawn triplets or closed kans
- No pon, open kan or added kan — closed only (a closed kan keeps the hand closed)
- A triplet completed by ron is open: on a shanpon wait it's suuankou only on tsumo
- On a single wait (four concealed triplets done, waiting on the pair) a ron counts too
Shanpon vs single wait
A suuankou tenpai comes in only two shapes.
Shanpon wait: tsumo only
Three concealed triplets and two pairs, waiting on two tiles. Draw either and it's suuankou; win by ron and that triplet becomes open, dropping you to sanankou + toitoi.
Tsumo
| Suuankou | Yakuman |
| Total | Yakuman · 8,000 / 16,000 points |
|---|
Non-dealer, East round, no dora, no honba.
Ron
| Toitoi | 2 han |
| Sanankou | 2 han |
| Total | 4 han 50 fu · Mangan · 8,000 points |
|---|
Non-dealer, East round, no dora, no honba.
Single wait: ron is fine, and it's a double yakuman
Four concealed triplets are complete and you wait on the pair. The winning tile only completes the pair, so even a ron is suuankou — here a suuankou tanki (double yakuman).
Ron
| Suuankou, single wait | 2× yakuman |
| Total | 2× yakuman · 64,000 points |
|---|
Non-dealer, East round, no dora, no honba.
How it relates to other yaku
- Sanankou: three concealed triplets, 2 han. Miss suuankou with a shanpon ron and you get sanankou + toitoi.
- Toitoi: suuankou is always four triplets, but a yakuman isn't added to regular yaku, so toitoi and sanankou aren't counted on top.
- Suukantsu, sankantsu: closed kans count as concealed triplets; four closed kans are suuankou + suukantsu.
- Other yakuman: suuankou stacks with tsuuiisou, daisangen and chinroutou — four concealed honor triplets is suuankou + tsuuiisou, a double yakuman.
Suuankou odds
Suuankou needs five kinds held as a pair or better (four triplets plus the pair), all drawn yourself. The more pairs you start with, the closer you are: a 13-tile starting hand has 4 or more pairs about 2.2% of the time, and 5 or more only 0.11%.
| Pairs in the starting hand | Chance |
|---|---|
| 1+ pairs | 87% |
| 2+ pairs | 50% |
| 3+ pairs | 15% |
| 4+ pairs | 2.2% |
| 5+ pairs | 0.11% |
Source: 1,000,000 random 13-tile deals.
In 40,000 hands (33,226 wins) between four normal-level computers on this site, suuankou (including the single wait) came up 2 times; all yakuman together came up 15 times, roughly once every 2,667 hands. The computers win as soon as they have a yaku and never keep pairs for suuankou, so treat the number as a rough guide.
Suuankou in other mahjong styles
- Taiwanese mahjong has "four concealed pungs" (Taiwanese mahjong tai list); with 16-tile hands there's five concealed pungs too
- Hong Kong mahjong: "All Concealed Pungs" is a limit hand (Hong Kong mahjong fan list)
- Chinese Official (Guobiao): "Four Concealed Pungs", 64 fan (Guobiao fan list)
To try it yourself, open a table of free online riichi mahjong — yakuman are scored for you too.
FAQ
Is Suuankou a yakuman?
Yes. Suuankou is a yakuman, and on a single wait it's a double yakuman by default in this game (you can turn that off in the lobby; Tenhou and M-League count it as a single yakuman).
Does a ron on a shanpon wait count as Suuankou?
No. The triplet completed by ron is open, leaving sanankou + toitoi. Only a tsumo gives suuankou. On a single wait there's no such problem — ron counts too.
Can a closed kan be part of Suuankou?
Yes. A closed kan counts as a concealed triplet and keeps the hand closed. Pon, open kan and added kan don't.
Do Suuankou and Chiitoitsu combine?
No. Chiitoitsu is seven different pairs; suuankou is four triplets and a pair. One hand can't be both.
Related yaku
Sanankou Closed 2 / open 2
Three self-drawn triplets, 2 han even when open. The shanpon-ron trap, why the fu are high, and how it differs from suuankou.
Toitoi Closed 2 / open 2
Four triplets and a pair, still 2 han when open. Examples, scoring combos and how many starting pairs you need.
Kokushi musou Yakuman（closed only）
One of each terminal and honor plus a pair — a yakuman. The 13-sided wait is a double yakuman here, the furiten trap, and what to do with nine terminals.
Try it at the table
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