Curriculum · 27 / 50
Shapes and efficiency: recap
This recap links wait shapes, blocks, ukeire and calls to compare objectively which discards move a hand toward tenpai.
The principle
The five basic waits do not have the same width. Ryanmen accepts up to eight tiles; kanchan and penchan up to four; shanpon up to four; tanki up to three. Visible copies reduce those maxima.
Rule and example
An ordinary hand seeks four groups and a pair. Block counting finds candidates, while shanten and ukeire compare discards. Complex shapes require several decompositions before counting the tiles that truly advance the hand.
What changes
An open call must preserve a yaku and deliver a concrete benefit. Its value depends on speed gained, score, remaining tiles and danger; a strategic answer is exact only when that context is specified.
Rules references
- Tenhou rulesReference profile used for game mechanics and scoring.
- WRC Rules 2025International rules compared whenever their options differ from Tenhou.