Houtei Raoyui (a Sino-Japanese term referring to winning a mahjong hand by the last player's discard) is an adult-themed mahjong game. The player assumes the role of a male student in a private high school, where he must compete against seven female opponents in the game of mahjong. The mahjong is always of the one-on-one variety. All the characters except the last one can be selected in any order from the main menu. If an opponent loses a mahjong match the player is rewarded with an erotic picture.