Shousangen
Shousangen 「小三元」 is a standard yaku, reliant on all three sangenpai. The hand is composed of two koutsu (triplet) and a jantou (pair) of the third type.
| Type | Yaku |
|---|---|
| Kanji | 小三元 |
| English | Small three dragons |
| Value | 2 han (Consider as 4 han) |
| Speed | Medium |
| Difficulty | Medium |
Tile pattern
Yasume: Takame:
This hand is a shousangen while winning on the cheaper winning tile. If it wins on the other tile, , it would give a daisangen yakuman instead.
Development
The hand requires two out of the four tile groups to be composed of dragon triplets, while the pair is always of the third type. That leaves two tile groups to be based off of any tile composition. Often enough but not always, such a hand may be tenpai for daisangen.
Compatibility
^ Ippatsu requires riichi to be of any use.
| RCH | DRI | IPP | SMO | TAN | PFU | IPK | ITT | YAK | SDJ | SDO | TOI | SNA | SNK | CHA | JUN | RPK | SSG | HRO | HON | CHN | CHI | RIN | HAI | HOU | CHK | |
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Shousangen requires two of the four tile groups to be dragon triplets, leaving no room for iitsu, ryanpeikou, sanshoku, and sanshoku doukou (which all require 3 groups). Chiitoitsu forbids metsu and is similarly incompatible. Naturally, pinfu, tanyao, junchan, and chinitsu are incompatible because of the dragon tiles.
Every shousangen hand always scores at least 2 yakuhai, from the two dragon tiles. Normally, when a yaku is guaranteed by another yaku, the guaranteed yaku is not scored. However, because shousangen does not guarantee any particular yakuhai (i.e., it does not guarantee "haku", "hatsu", or "chun"), the two yakuhai are scored.
Value
In general, this yaku is noted as 2 han. However, it is impossible for this yaku to score without two instances of yakuhai from the two groups of sangenpai. In combination, this yaku will never produce a hand worth less than 4 han. Even with both sangenpai groups called open, that is a combination of 8 fu; and then there's 2 more fu from the sangenpai pair of the third type. The hand will almost always score at least mangan.
The lowest scoring shousangen is valued at 4 han 30 fu. The requirements to do so, assuming no additional yaku, are:
- The hand must be won by ron, as a tsumo would score 2 fu.
- The wait must be either a ryanmen or shanpon wait, as any other wait would score 2 fu.
- Both of the other groups must be shuntsu of different suits. If either was a koutsu, it would score at least 2 fu.
- Both of the yakuhai groups must be open, as they would score additional fu if closed. Note that as this is for the purposes of counting fu, if a group is completed by ron, it counts as being open.
- Neither of the yakuhai groups may be kantsu, as they would score additional fu as kantsu.
Two examples scoring exactly 4 han 30 fu on a ron:
Agari: 
Agari:
External links
- Shousangen in Japanese Wikipedia