Chiniisou
Chiniisou 「清一色」 is a standard yaku, scored when the hand composed of tiles in one numbered suit only. Chinitsu is worth 6 han, but it decreases to 5 han when opened. This yaku is usually referred to as chinitsu or, occasionally, chinichi.
| Type | Yaku |
|---|---|
| Kanji | 清一色 |
| English | Flush |
| Value |
6 han (closed) 5 han (open) |
| Speed | Slow |
| Difficulty | Medium |
Tile patterns
Using pinzu:
Waiting for:
Using manzu:
Waiting for: 
Using souzu:
Waiting for: 
Formation
As defined, this yaku is formed by collecting tiles of one suit. Therefore, tiles not of a particular suit are regularly discarded. As a consequence, a player aiming for a chinitsu may be very easily detected via discards alone.
Complex wait patterns
Chinitsu is notorious for developing complex wait patterns. Since all 13 tiles are of one suit, it is easy for groups to mix together, forming multi-sided waits. If playing without computers, it can be difficult to tell what your waits are.
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 | |
| CHN |  |
|
|
|
|
|
|
|
 |
|
|
|
|
|
 |
|
|
|
|
|
|
|
|
|
|
Chinitsu requires a single suit with no honors. Yakuhai, shousangen, sanshoku, and sanshoku doukou all require honors or multiple suits, and are thus incompatible. Chinitsu implies honitsu, so they are not counted together. If combined with chanta, the hand is actually junchan, so that yaku is counted instead. Finally, chinitsu and honroutou would require a hand containing at most eight tiles (the 1s and 9s of one suit), which is impossible.
Value
As a standalone yaku, chinitsu is at least a mangan, even when open. To regain the lost han as an open hand, it simply takes a dora, or another yaku, to bring the hand up to its closed value of a haneman.
Yakuman
Due to the relatively high value of this yaku, chinitsu may be involved in the formation of kazoe yakuman, especially when closed. The 6-han from closed chinitsu is almost half the requirement for 13-han; naturally, other yaku and/or dora will need to provide the next. Though, one particular pattern may form as a true yakuman, chuuren poutou.
External links
- Chiniisou in Japanese Wikipedia
- Game designed with sou tiles only to train reading chinitsu hands.