Logic Masters Deutschland e.V.

Rules:

1. Normal sudoku rules apply.
2. Each of the eight delimited regions contains a valid Riichi Mahjong Chinitsu (Full Flush) hand. A valid hand is a 14-tile hand that generally consists of four melds and a pair, a meld being either a sequence/Chow (three consecutive digits) or a triplet/Pung (three identical digits). For instance, 11133345567777 is a valid hand (111 + 33 + 345 + 567 + 777). The only exception to this rule is that Seven Pairs is also allowed (11334466778899 is valid!).
3. Specific harmonies (Yaku) exist in Mahjong that allow us to classify the hands. Here are the harmonies we are interested in:
   • 断幺九 (All Simples): the hand does not contain any 1 nor 9. 22234566777888 is a valid All Simples hand (222 + 345 + 66 + 777 + 888).
   • 対々 (All Pungs): the hand can be considered as specifically four triplets and one pair (no chows). 11144666777888 is a valid All Pungs hand.
   • 平和 (Pinfu): the hand can be considered as specifically four sequences and one pair (no triplets). 12233344555678 is a valid Pinfu hand (123 + 234 + 345 + 55 + 678).
   • 一通 (Pure Straight): the hand contains the sequences 123, 456, and 789. 12233445677789 is a valid Pure Straight hand (123 + 234 + 456 + 77 + 789). Note that even if all digits from 1 to 9 are included and the hand is valid, a hand such as 12233456778999 (123 + 234 + 567 + 789 + 99) is not considered as Pure Straight (no way to make the hand valid when isolating the three sequences 123, 456, and 789).
   • 一盃口 (Double Chow): the hand contains twice the same sequence. 11223334566677 is a valid Double Chow hand (123 + 123 + 345 + 666 + 77). All Pungs always takes precedence over Double Chow, meaning 11144666777888 will be considered as (111 + 44 + 666 + 777 + 888) and not (111 + 44 + 678 + 678 + 678) and therefore will not be considered Double Chow.
   • 二盃口 (Twice Double Chow): the hand contains two pairs of twice the same sequence. 11223355667777 is a valid Twice Double Chow hand (123 + 123 + 567 + 567 + 77). Twice Double Chow is not compatible with Seven Pairs (and Twice Double Chow is always preferred over Seven Pairs when it is ambiguous).
   • 純全 (Outside Hand): the five groups contain at least a 1 or a 9. 11112377889999 is a valid Outside Hand (111 + 123 + 789 + 789 + 99).
   • 九連宝燈 (Nine Gates): the hand follows the form 1112345678999 + one additional digit. You can convince yourself that adding any other numbered tile will make a valid hand. 11122345678999 is an example of valid Nine Gates (111 + 22 + 345 + 678 + 999).
   • 七対子 (Seven Pairs): the hand does not follow the normal Mahjong structure, but instead consists of seven distinct pairs. 11335566778899 is a valid Seven Pairs hand. 11223355667788 is not Seven Pairs but rather Twice Double Chow. 11112233557788 is not a valid hand.

ALL harmonies present in each of the eight regions are listed (meaning, if a harmony is not listed, it is not present!)

You can play via the interactive website which checks Mahjong hands automatically and contains a Yaku checker.

Grid with Yaku names in English: