Iipeikou

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Iipeikou 「一盃口」 is a yaku scored when a hand has two identical sequences (two sequences with the same number and suit). It also requires the hand to be closed. If a hand has "two iipeikou"s, it instead scores ryanpeikou.

Iipeikou
Type Yaku
Kanji 一盃口
English Identical sequences
Double sequences
Value 1 han (closed only)
Speed Medium
Difficulty Easy

Tile pattern

              

Rearrangement

              

Arrangement of tiles is irrelevant, as long as two groups of tiles form the identical sequences.

Formation

When the tiles are sorted, iipeikou may appear as three groups of consecutive pairs. However, since they must be interpreted as two sequences to score as iipeikou, a hand can never score both iipeikou and chiitoitsu.

Note that iipeikou requires the hand to be closed, so any open call (chii/pon/open kan) will invalidate this yaku, even if the call was unrelated to this yaku. However, it is allowed to call ron and score this yaku, even if the winning tile was the one to complete the iipeikou pattern.

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
IPK                                                  

Iipeikou requires two sequences, and as a result is incompatible with sanshoku doukou, toitoi, honroutou, chiitoitsu, sanankou, and sankantsu, all of which require either at least three koutsu/kantsu or a seven pair structure. The final incompatibility is with ryanpeikou, as ryanpeikou implies iipeikou and so iipeikou is not counted.

Iipeikou is often combined with pinfu, which also requires sequences. Iipeikou can naturally be obtained with shapes like 4456 and 4556, which a pinfu hand may have due to tile efficiency reasons.

External links

Iipeikou in Japanese Wikipedia