2) Additional rule Shingou (心狗), an old Japanese Mahjong (Riichi) variant, in the event a player drops a tile from his/her playing hand on accident onto the floor, the guilty player then loses the tile's ownership and the proprietary of that tile will be open to other opposing players to claim by picking it up and adding it to their hand hence revoking both player's winning condition, one having a 大相公 and 小相公. However, this rule is best confirmed with other players before the match.