Riichi

Riichi is the most commonly used yaku in the game. This yaku may apply to any closed hand and may be declared upon achieving tenpai. Due to its common usage, various specific game scenarios must be considered when using riichi.

Rules to riichi

After any time a player has a closed tenpai hand, the player may declare riichi. Upon doing so, the hand instantly gains the potential to win 1 han. To declare riichi, a player announces riichi and deposits 1000 points onto the table. Then the player discards a tile facing sideways in the discard pile. This is done to indicate when riichi was called. If that tile is claimed by another player, then the next discard is turned sideways as a replacement. After a riichi declaration, the hand remains locked and unchangeable; in this state, the player is simply waiting for a winning tile to appear, either by draw or discard.

Ippatsu

This yaku is awarded, if the player receives a winning tile within 4 tile draws and discards after declaring riichi. However, this yaku is invalided, if tile calls interrupt during this process.

Double riichi

Double riichi is a special case for riichi, where the player declares riichi with a dealt hand.