12 · Special hand
Conditions
All nine tiles of 147, 258 and 369 assigned to three different suits. These nine tiles do not form chow-combination patterns, but still count for whole-hand patterns such as All Chows, All Types and No Honors.
How to build it
Check the required distinct tiles and pairs early. These hands often differ from four sets and a pair, so avoid calls that destroy the target shape.
Key tile shapes
Patterns not counted together
No separate exclusions