A yaku is a scoring condition in Japanese riichi. Without one you cannot win, even if the shape is four sets and a pair.
Riichi itself is a yaku. Other yaku come from the shape of the hand or the state of the table.
American mahjong does not use this word. It reads a printed line.
No yaku, no win
Riichi itself is a yaku. Other yaku come from the shape of the hand or the state of the table. Even if the shape is four sets and a pair, you cannot win without a yaku.
American mahjong does not use this word. It reads a printed line.