Round wind

The round wind, also called the prevalent or prevailing wind, is the wind that applies to every player at the table during the current round of play. Games begin in the East round; once each player has dealt (and the rotation completes without extra repeats), play advances to the South round, then West and North in longer formats. A half-game (hanchan) in Riichi runs East and South rounds, while an East-only (tonpuusen) game uses just the East round.

In Riichi the round wind is a yakuhai: a triplet or kong of the prevailing wind tile scores 1 han for any player, regardless of where they sit, and validates an otherwise yaku-less hand. This differs from the seat wind, which is personal to one player. The two can stack: during an East round the East player's East triplet counts as both round and seat wind for 2 han. For example, in a South round any player completing a pung of 2z (South) earns the round-wind han.

A common confusion is assuming the round wind changes with each hand the way the dealership rotates — it does not. The round wind stays fixed across all the hands that make up one full round and only advances when the rotation completes. In Chinese MCR the equivalent 'Pung of Round Wind' is a minor scoring pattern, and various house rules cap games at the East and South rounds to keep sessions short. Tracking the round wind matters because it tells you which honor tiles are live value tiles for everyone and which are safe-ish discards once their value windows have passed.