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Reading complex shapes
Complex shapes combine several possible runs, pairs and waits; decomposing them in multiple ways reveals their true ukeire.
The principle
A compact shape can hold several overlapping blocks. To read it, list every possible run, pair and incomplete group, then place the remainder back into the full hand. One tile may belong to several candidate readings, but only one final decomposition.
Rule and example
Shapes such as 2334 or 4556 gain flexibility from that overlap: depending on the next draw, they can produce a run, pair or two-sided shape. Their value is not just the number of distinct ranks; calculate which tiles truly reduce shanten after each discard.
What changes
Visible copies matter. A theoretical improvement loses value when three or four copies are already exposed. The reliable method is to compare, for each discard candidate, resulting shanten, accepted tile types and the number of copies still unseen. This is an upper bound because an unseen copy may be in an opponent’s hand or the dead wall.
Rules references
- Tenhou rulesReference profile used for game mechanics and scoring.
- WRC Rules 2025International rules compared whenever their options differ from Tenhou.