Ryanpeikou
| Type | Yaku |
|---|---|
| Kanji | 二盃口 |
| English | Two sets of identical sequences |
| Value | 3 han (closed only) |
| Speed | Very slow |
| Difficulty | Very hard |
Ryanpeikou 「二盃口」 is a standard yaku, consisting of two "iipeikou". The prefix "ryan" is a Japanese counter for mahjong, signifying for "two".
Tile pattern
Agari:
Note: This hand may also win with 
. However, it'll only count for a lesser value of iipeikou (and pinfu).
Formation
At the very least, the hand must initially qualify for the yaku, iipeikou. With tenpai, the tile wait involves a tanki, to complete the pair, or the need to complete the other "iipeikou".
Like iipeikou, ryanpeikou requires the hand to be closed. Declaring ron with closed hand is fine, even if the ron'd tile completed this yaku.
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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Ryanpeikou is incompatible with other yaku that place conflicting requirements on the mentsu in the hand. Ittsu, sanshoku, sanshoku doukou, toitoi, sanankou, sankantsu, and shousangen are excluded as they are require either three different sequences or at least one triplet/quadruplet. Rinshan kaihou also requires a kan, so it is excluded. Chankan is incompatible because the winning tile must be unique in the winning hand---all four copies of it having been used in another player's kan. Finally, iipeikou is incompatible because it is superseded by ryanpeikou.
Chiitoitsu
This yaku cannot combine with chiitoitsu. By definition, chiitoitsu is formed by the collection of seven distinct pairs. In most instances of ryanpeikou, the hands look like chiitoitsu hands. However, ryanpeikou is actually composed of sequences, rather than as independent pairs. Because of this interpretation, the two yaku remain distinct and incompatible. It is doubtful that any house rule allows the combination of the two yaku.
Note that not all instances of ryanpeikou could have qualified for chiitoitsu. The following, for instance, is a valid ryanpeikou hand:
Agari:
With chinitsu
Some forms of ryanpeikou mixed with chinitsu and tanyao may actually form some optional yakuman, named daisharin (pinzu), daichikurin (souzu), and daisuurin (manzu).
Agari: , , or
Value
Ryanpeikou can only be scored closed, and is always worth 3 han. So there is no need to be concerned about the hand losing value when open. The cheapest ryanpeikou hand uses either a kanchan / penchan / tanki wait, or a ryanmen wait with valued honor as the pair. In both cases, the hand produces a 3-han and 40-fu value by ron. By tsumo, it is 4-han and 30-fu.
External links
- Ryanpeikou in Japanese Wikipedia
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