Iipeikou

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Revision as of 17:39, 17 April 2024 by Hordes (talk | contribs) (extra clarify the conditions for iipeikou)
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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 involving two identical sequences. Identical means that both shuntsu must be of the same numbers and suit. This yaku also requires the hand to be closed. Any open call ruins the yaku, even if the pattern already existed within the hand. If this pattern is found twice in one hand, an alternative yaku, ryanpeikou, is scored.

Tile pattern

Rearrangement

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

Formation

This yaku usually appears 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.

Note that iipeikou requires the hand to be closed. If you make any open call (chii/pon/open kan), iipeikou can never be scored, even if the call was unrelated to the identical sequences. However, the sequences do not have to be closed: if you declare ron with a closed hand, iipeikou can still be scored, even if the winning tile completed the 2nd identical sequence.

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