jp mahjongJapanese Mahjong How to play Mahjong. Riichi (1 fan) When your hand is ready and fully concealed, you can call Riichi. Daburu-Riichi (2 fan) First turn Riichi. Ippatsu (1 fan) WinningIn Japanese mahjong, yaku (Japanese: ) is a condition that determines the value of the player's hand. It is essential to know the yaku for game strategy