Iipeikou

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

Iipeikou 「一盃口」 is a standard yaku. Its feature composes of two identical sequences. By identical, both shuntsu must be of the same number and same suit. This pattern may also be produced twice in one hand, to form an alternative yaku, ryanpeikou. Finally, the hand must be closed only. A single open call invalidates the yaku, even if the pattern exists within the hand.

Tile pattern

Rearrangement

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

Formation

This yaku is usually presented as three groups of consecutive pairs. However, the rule interpretation views them as a two sequences. Potential acquisition of this yaku is best recognizable when five out of the six tiles are present in the hand.

Compatability

Main article: Yaku compatability

^ 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.