Iipeikou: Difference between revisions

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

VisualWikitext

Latest revision as of 11:23, 25 August 2024

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.

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

Main article: 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
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

一盃口

Iipeikou in Japanese Wikipedia

@@ Line 8: / Line 8: @@
 |gameExample = * [http://tenhou.net/0/?log=2014011309gm-0009-7447-f766aece&tw=0&ts=4 Iipeikou] with [[damaten]]
 }}
-'''Iipeikou''' {{kana|一盃口}} is a standard [[yaku]].  Its feature composes of two identical [[mentsu#shuntsu|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 [[naki|open call]] invalidates the yaku, even if the pattern exists within the hand.
+'''Iipeikou''' {{kana|一盃口}} is a [[yaku]] scored when a hand has two identical [[sequence]]s (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]].
 ==Tile pattern==
@@ Line 21: / Line 21: @@
 ==Formation==
-This yaku is usually presented as three groups of consecutive pairs.  However, the rule interpretation views them as a two [[shuntsu|sequences]].  Potential acquisition of this yaku is best recognizable when five out of the six tiles are present in the hand.
+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]].
-=== Compatability ===
+Note that iipeikou requires the hand to be closed, so any [[naki|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.
-{{main|Yaku compatability}}
+== Compatibility ==
+{{main|Yaku compatibility}}
 {{Yaku compatibility table|IPK}}
@@ Line 30: / Line 32: @@
 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.
-=== Common combinations ===
+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.
-==Value==
-{{yaku value|width = 40% |align = right
-<!--Minimum for ron-->
-| comment1          = Minimum possible
-| ronhanfumin       = 1 - 40
-| ronnondealermin   = 1300
-| rondealermin      = 2000
-<!--Minimum for tsumo-->
-| comment2          = With mentsumo
-| tsumohanfumin     = 2 - 30
-| tsumonondealermin = 1000/500
-| tsumodealermin    = 500
-<!--Maximum for ron-->
-| comment3          = Maximum without other yaku
-| ronhanfumax       = 1 - 100
-| ronnondealermax   = 3200
-| rondealermax      = 4800
-<!--Maximum for ron-->
-| comment4          = With mentsumo
-| tsumohanfumax     = 2 - 100
-| tsumonondealermax = 3200/1600
-| tsumodealermax    = 3200
-}}
-{{main|Scoring}}
-This yaku is required to be closed only.  Even if the pattern exists within an open hand, the yaku will not be counted in this case.
-* '''Minimum''' ''(Iipeikou only)''
-: {{#mjt: 556677p13m44466s}} Agari: {{#mjt: 2m}}
-* '''Maximum''' ''(Iipeikou only, when not seated north)''
-: {{#mjt: 556677s1z}} {{#mjt:0z11s00440z}} Agari: {{#mjt: 1z}}
-The lowest possible score for a iipeikou nomi (only) hand is 1 han and 40 fu.  The 40 fu is derived from a closed ron (10 fu) plus possession of another fu generated form, either by certain [[machi|wait patterns]] or [[koutsu|triplet(s)]].  In order for the hand to involve 30 fu, it would have to involve pinfu with the closed ron.  Likewise, a win by tsumo may involve a similar form.  Given the closed only aspect of this hand, it is unavoidable to score an "iipeikou only" hand without a combination with [[mentsumo|closed tsumo]].
-The highest possible score for an iipeikou nomi (only) hand is 1 and 100 fu.  The 64 fu is derived from two groups of non-yakuhai [[jihai|honor tiles]] or [[terminal|terminals]] used for [[kan|closed kans]].  With that, the wait pattern involves a [[tanki|single wait]] on the East round dealer win pair; the pairing brings in 6 fu (4 for the double wind and 2 for the single wait).  Add the base fu and closed ron, and the total fu count is exactly 100.  For tsumo, the difference again involves a closed tsumo and the lack of 10 fu derived from a closed ron.  However, it surpasses 90 fu from the tsumo bonus and rounds up to 100 anyways.  Naturally, when combined with other yaku, the score can be significantly higher.
 ==External links==