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Reading opponent waits
A concealed wait cannot be known from discards alone; combine genbutsu, suji, kabe, calls and visible tiles to rank risk.
The principle
Against a given player, their own discards are genbutsu and safe for ron because of furiten. After riichi, any tile that passes without ron also becomes safe against that player. This safety does not apply to other opponents and does not prevent tsumo.
Rule and example
Suji reduces some ryanmen risk without excluding kanchan, penchan, tanki or shanpon. A four-tile kabe makes certain sequences impossible; one-chance leaves one possible copy and is much weaker. None of these clues has the certainty of genbutsu.
What changes
Calls, visible tiles and discard order rank possibilities rather than identify one exact wait. A sound read therefore states relative risk and its exceptions, then weighs that risk against hand value and the likely cost of a ron.
Rules references
- Tenhou rulesReference profile used for game mechanics and scoring.
- WRC Rules 2025International rules compared whenever their options differ from Tenhou.