Iishanten: Difference between revisions
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'''Iishanten''' is the state of | '''Iishanten''' is the state of a hand where one tile is needed to achieve [[tenpai]]. This is the [[Shanten|closest state]] to tenpai. | ||
== | == Four main types == | ||
The four types are based on the possible configurations regarding complete and incomplete [[tile groups]]. | The four types are based on the possible configurations regarding complete and incomplete [[tile groups]]. | ||
=== Yojouhai === | === Yojouhai === | ||
{{#mjt:234m2378s22567p1z}} | {{#mjt:234m2378s22567p1z}} Waiting for: {{#mjt:1469s}} (to form a sequence) | ||
'''Floating tile iishanten''' {{kana|余剰牌}} | '''Floating tile iishanten''' {{kana|余剰牌}} is a hand with two complete groups and a pair, with two incomplete groups waiting to be completed. One tile (the East tile in the example hand) does not contribute to any group, and so is said to be floating. | ||
=== Kanzenkei === | === Kanzenkei === | ||
{{#mjt:234m22378s22567p}} | {{#mjt:234m22378s22567p}} Waiting for: {{#mjt:1469s}} (to form a sequence), {{#mjt:2s2p}} (to form a triplet) | ||
'''Complete iishanten''' {{kana|完全形、完全イーシャンテン}} is an improvement on floating iishanten | '''Complete iishanten''' {{kana|完全形、完全イーシャンテン}} is an improvement on floating iishanten where all tiles in the hand contribute to the iishanten. In the example hand, the 223s group now has three tiles working together. | ||
This hand is also an example of '''perfect iishanten'''. Perfect iishanten is a complete iishanten with two ryanmen groups, thus guaranteeing a ryanmen wait. | |||
=== Atamanashi === | === Atamanashi === | ||
{{#mjt:123m2378s456789p}} | {{#mjt:123m2378s456789p}} Waiting for: {{#mjt:1469s}} (to form a sequence), {{#mjt:2367s}} (to form a pair) | ||
'''Headless iishanten''' {{kana|頭なし、ヘッドレス}} is a hand with three complete groups, no pair, and one/two incomplete groups. An ideal headless hand, as shown above, will have two ryanmen groups waiting to be completed. If either ryanmen is completed, the hand enters tenpai with a tanki wait. If any of the four tiles are paired, the other tile of its group can be discarded, forming a wait with the other ryanmen. (E.g. if a 2s is drawn, discard 3s to enter a ryanmen tenpai.) | |||
'''With a triplet''' | |||
{{#mjt:123m2378s222789p}} Waiting for: {{#mjt:1469s}} (to form a sequence), {{#mjt:2367s}} (to form a pair) | |||
'''Headless iishanten + closed triplet''' is a stronger version of headless iishanten. Here, if either ryanmen is completed, then the triplet can be discarded (turning it into a pair), thus retaining a ryanmen wait. | |||
Assuming the hand has two ryanmen groups: | |||
* A headless iishanten without a triplet has better tile acceptance than a perfect iishanten, but there are fewer tiles that lead to a ryanmen wait at tenpai. | |||
* A headless iishanten with a triplet has better acceptance than perfect iishanten, and has more tiles that end with a ryanmen wait. | |||
=== Kuttsuki === | === Kuttsuki === | ||
{{#mjt:234678m37s22567p}} | {{#mjt:234678m37s22567p}} Waiting for: {{#mjt:123456789s}} (to form a group) | ||
'''Sticky iishanten''' {{kana|くっつき}} is a hand with three complete groups, one pair, and two floating tiles. This type of iishanten tends to accept the most tiles, but many of those tiles lead to a non-ryanmen wait. | |||
== Chiitoitsu == | == Chiitoitsu == | ||
{{main|Chiitoitsu}} | {{main|Chiitoitsu}} | ||
{{#mjt:1166m4499s667p25z}} | {{#mjt:1166m4499s667p25z}} Waiting for: {{#mjt:7p25z}} (to form a pair) | ||
A hand is iishanten for chiitoitsu when the hand has five pairs. This leaves three individual tiles waiting to be paired. | |||
If one of the tiles is part of a triplet, it becomes easier to convert the hand to [[toitoi]], but only two tiles can be paired. | |||
== Kokushi musou == | == Kokushi musou == | ||
{{main|Kokushi musou}} | {{main|Kokushi musou}} | ||
'''11 unique tiles, 1 pair''' | |||
{{#mjt: 1m139p19s1234566z}} Waiting for: {{#mjt:9m7z}} (to enter a 1-sided wait) | |||
'''12 unique tiles''' | |||
{{#mjt: 19m139p19s123456z}} Waiting for: {{#mjt:7z}} (to enter a 13-sided wait), {{#mjt: 19m19p19s123456z}} (to enter a 1-sided wait) | |||
==External links== | ==External links== | ||
Revision as of 22:24, 24 July 2024
Iishanten is the state of a hand where one tile is needed to achieve tenpai. This is the closest state to tenpai.
Four main types
The four types are based on the possible configurations regarding complete and incomplete tile groups.
Yojouhai
Waiting for: 
(to form a sequence)
Floating tile iishanten 「余剰牌」 is a hand with two complete groups and a pair, with two incomplete groups waiting to be completed. One tile (the East tile in the example hand) does not contribute to any group, and so is said to be floating.
Kanzenkei
Waiting for: (to form a sequence), (to form a triplet)
Complete iishanten 「完全形、完全イーシャンテン」 is an improvement on floating iishanten where all tiles in the hand contribute to the iishanten. In the example hand, the 223s group now has three tiles working together.
This hand is also an example of perfect iishanten. Perfect iishanten is a complete iishanten with two ryanmen groups, thus guaranteeing a ryanmen wait.
Atamanashi
Waiting for: (to form a sequence), (to form a pair)
Headless iishanten 「頭なし、ヘッドレス」 is a hand with three complete groups, no pair, and one/two incomplete groups. An ideal headless hand, as shown above, will have two ryanmen groups waiting to be completed. If either ryanmen is completed, the hand enters tenpai with a tanki wait. If any of the four tiles are paired, the other tile of its group can be discarded, forming a wait with the other ryanmen. (E.g. if a 2s is drawn, discard 3s to enter a ryanmen tenpai.)
With a triplet
Waiting for: (to form a sequence), (to form a pair)
Headless iishanten + closed triplet is a stronger version of headless iishanten. Here, if either ryanmen is completed, then the triplet can be discarded (turning it into a pair), thus retaining a ryanmen wait.
Assuming the hand has two ryanmen groups:
- A headless iishanten without a triplet has better tile acceptance than a perfect iishanten, but there are fewer tiles that lead to a ryanmen wait at tenpai.
- A headless iishanten with a triplet has better acceptance than perfect iishanten, and has more tiles that end with a ryanmen wait.
Kuttsuki
Waiting for: 
(to form a group)
Sticky iishanten 「くっつき」 is a hand with three complete groups, one pair, and two floating tiles. This type of iishanten tends to accept the most tiles, but many of those tiles lead to a non-ryanmen wait.
Chiitoitsu
Waiting for: (to form a pair)
A hand is iishanten for chiitoitsu when the hand has five pairs. This leaves three individual tiles waiting to be paired.
If one of the tiles is part of a triplet, it becomes easier to convert the hand to toitoi, but only two tiles can be paired.
Kokushi musou
11 unique tiles, 1 pair
Waiting for: 
(to enter a 1-sided wait)
12 unique tiles
Waiting for: (to enter a 13-sided wait), (to enter a 1-sided wait)
External links
- Iishanten in Japanese Wikipedia
- 【麻雀】上がりを増やす！イーシャンテンの秘密【初心者向け講座】 (YouTube)
- Video covering iishanten shapes