Yaku compatibility

This is a table showing the compatibilities of the different yaku with each other. While yaku may be combined in one hand, it is simply impossible to combine certain yaku with each other. This can arise for two reasons:

  1. Conflicting definitions. Tanyao requires the hand contains no honor tiles, but yakuhai requires a triplet of honor tiles, so the two cannot be combined.
  2. 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 mandates that the hand has a terminal or honor in each group. Every junchan hand is also a chanta hand, so chanta is not scored. By rule, two yaku cannot be combined if one always implies the other. (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".)
A single hand composed of six yaku to produce a baiman hand.

Yaku

Key
Abbrevation Yaku
RCH Riichi
DRI Double riichi
IPP Ippatsu
SMO Mentsumo
TAN Tanyao
PFU Pinfu
IPK Iipeikou
ITT Ittsu
YAK Yakuhai
SDJ Sanshoku doujun
SDO Sanshoku doukou
TOI Toitoi
SNA Sanankou
SNK Sankantsu
CHA Chanta
JUN Junchan
RPK Ryanpeikou
SSG Shousangen
HRO Honroutou
HON Honitsu
CHN Chinitsu
CHI Chiitoitsu
RIN Rinshan
HAI Haitei
HOU Houtei
CHK Chankan

Yaku strategy involves viability to form yaku and maximizing hand value, if possible. This maximization often involves the recognition of the different yaku forming in one hand. Often, this affects the decision which tiles to keep and which to discard.

Three combinations actually form yakuman:

  • Toitoi + Junchan = Chinroutou
  • Toitoi + Mentsumo = Suuankou
  • Honroutou + Junchan = Chinroutou
  • Double riichi + Chankan is only possible with a Kokushi musou hand

Some combinations form a different yaku which implies one component of the combination, and as a result can never be counted:

  • Toitoi + Chanta = Toitoi + Honroutou
  • Chiitoitsu + Chanta = Chiitoitsu + Honroutou
  • Honitsu + Tanyao = Chinitsu + Tanyao
  • Honitsu + Junchan = Chinitsu + Junchan
  • Chinitsu + Chanta = Chinitsu + Junchan

These combinations are marked with   in the table below.

Whether or not these combinations are actually combinations depends on the technical definition of the yaku. Some yaku are restricted versions of other yaku, 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.

Nagashi mangan is excluded, because it is incompatible with anything, even riichi.

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
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                                                  

Yakuman

Even different yakuman may be combined. As a result, point values may increase beyond single yakuman values as multiples of yakuman. Of course, that's only if the rules allow extension into double yakuman and beyond. Combinations involving three kinds of yakuman involve either tsuuiisou, tenhou, or chiihou. With this in mind, the options for combining different yakuman are limited.

Compatibility

KMU DSG SUA SSS DSS TSU RYU CHR CHU SUK TEN CHH
Kokushi musou KMU                      
Daisangen DSG                      
Suuankou SUA                      
Shousuushii SSS                    
Daisuushii DSS                    
Tsuuiisou TSU                      
Ryuuiisou RYU                      
Chinroutou CHR                      
Chuuren poutou CHU                      
Suukantsu SUK                      
Tenhou TEN                    
Chiihou CHH                    

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