Yaku compatibility: Difference between revisions

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# Conflicting definitions. [[Tanyao]] requires the hand contains no honor tiles, but [[yakuhai]] requires a triplet of honor tiles, so the two cannot be combined.
# Conflicting definitions. [[Tanyao]] requires the hand contains no honor tiles, but [[yakuhai]] requires a triplet of honor tiles, so the two cannot be combined.
# When a yaku always implies another yaku, they cannot score together. For instance, a [[junchan]] hand has a terminal in every group. This also fits the definition of [[chanta]], which requires that the hand has a terminal or honor in each group. Because every junchan hand would also qualify for chanta, chanta is not scored.
# When a yaku always implies another yaku, they cannot score together. For instance, a [[junchan]] hand has a terminal in every group. Chanta requires that the hand has a terminal or honor in every group. Because every junchan hand would also qualify for chanta, chanta is not scored.
:(A partial exception is with [[shousangen]]. Shousangen always implies two dragon yakuhai, but does not always imply you have any one of "haku", "hatsu", or "chun".)


Because of reason #2, there are a few other combinations that are impossible.
When two yaku imply each other, as with reason #2, there are two alternate ways to define it in the rules:
*"Alter the yaku definitions so that they can never be scored together". For example, Chanta is scored when there are honors/terminals in each group, and the hand ''must'' contain at least one honor tile.
*"Yaku that imply each other cannot be scored". Chanta is scored when there are honor/terminals in each group (not requiring an honor tile). However, chanta and junchan are never scored together.
 
Most of these combinations, with the exception of toitoi + mentsumo, are based on the assumption that the yaku are defined using the second method.
 
===Indirectly illegal===
There are a few combinations that are indirectly impossible due to the implication rule.


Four combinations actually form yakuman:
Four combinations actually form yakuman:
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These combinations are marked with {{or}} in the table below.
These combinations are marked with {{or}} in the table below.
Whether or not these combinations are actually combinations depends on the technical definition of the yaku. When yaku imply each other, such as junchan and chanta, there are two alternative ways to define this in the rules:
*Chanta is scored when there are honors/terminals in each group, and ''requires'' that the hand contains at least one honor tile.
*Chanta is scored when there are honors/terminals in each group (not requiring an honor tile). However, if a hand is eligible for both chanta and junchan, only one can be scored. Since junchan is the more valuable yaku, it is always the one scored.
Most of these combinations, with the exception of toitoi + mentsumo, are based on the assumption that the yaku are defined using the second method.


== Yaku ==
== Yaku ==
1,758

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