Riichi: Difference between revisions

rw kan after riichi, move double riichi compat to the double riichi page
(rw kan after riichi, move double riichi compat to the double riichi page)
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{{main|Kan#Kan during riichi}}
{{main|Kan#Kan during riichi}}


Kan during riichi is a discretionary play. Players must take note of the hand composition to determine whether the kan is allowable or not. If the call alters the hand's waiting pattern or alters the hand's composition, kan is not allowed. Improper calls are subject to chombo if detected.
You are able to declare a closed [[kan]] after a riichi. When this is legal will depend on the ruleset; improper calls may be subject to [[chombo]]. See [[Kan#Kan during riichi|Kan during riichi]] for more details. Even if the kan is legal, you may or may not want to declare one.


=== Furiten ===
=== Furiten ===
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=== Open riichi ===
=== Open riichi ===
'''Open riichi''' {{kana|オープン立直}} is an [[optional yaku]] which is a modified version of riichi. The mechanics are identical to a normal riichi, except that you must reveal either your entire hand or its tile [[wait]]s. In exchange, an open riichi is worth 1 extra han. Open riichi makes it trivial for other players to defend against your hand, so in general, the intent is to win by self-draw.
'''Open riichi''' {{kana|オープン立直}} is an [[optional yaku]] which is a modified version of riichi. The mechanics are identical to a normal riichi, except that you must reveal either your entire hand or its tile [[wait]]s (depending on ruleset). In exchange, an open riichi is worth 1 extra han. Open riichi makes it trivial for other players to defend against your hand, so in general, the intent is to win by self-draw.


As a further optional rule, yakuman may be awarded if any player intentionally [[ron|plays into]] the open riichi. If a player unintentionally deals in, i.e. if a riichi player deals into an open riichi, the yakuman is not scored.  
As a further optional rule, yakuman may be awarded if any player intentionally [[ron|plays into]] the open riichi. If a player unintentionally deals in, i.e. if a riichi player deals into an open riichi, the yakuman is not scored.  
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Once again, the prospect for [[rinshan kaihou]] to work with riichi is dependent on the legality of the [[Riichi#Kan_during_riichi|kan call during riichi]].  With computer interfaces, this rule may be enforced by disabling a player's ability to call the kan during this situation.  However, with actual tiles, a player must be aware of this legality.  Otherwise, chombo may be enforced instead.
Once again, the prospect for [[rinshan kaihou]] to work with riichi is dependent on the legality of the [[Riichi#Kan_during_riichi|kan call during riichi]].  With computer interfaces, this rule may be enforced by disabling a player's ability to call the kan during this situation.  However, with actual tiles, a player must be aware of this legality.  Otherwise, chombo may be enforced instead.
=== Double riichi ===
Double riichi has the same compatibility as riichi, except for [[chankan]]. This is because, for a regular hand, chankan may only be formed from an [[Kan#Shouminkan|added kan]], which itself requires a call for [[pon]] to happen first.
* If the pon call happens before the riichi call, then double riichi is negated.
* If the pon call happens after the riichi call, then the double riichi player must have declined their winning tile, invoking [[furiten]]. Chankan can only be won from [[ron]], so furiten prevents chankan entirely.
An exception is the yakuman [[kokushi musou]]. Depending on [[Kokushi_musou#Chankan_rule_variation|rule variation]], kokushi may be won off a [[ankan|closed kan]], which does not require a previous pon call. Therefore, in order to win with double riichi + chankan, it must also have kokushi. Since this would be a yakuman hand, the yaku of "chankan" is never actually scored.


== Strategy ==
== Strategy ==
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