Crazyhouse (also known as drop chess, mad chess, reinforcement chess, turnabout chess and schizo-chess) is a chess variant in which captured enemy pieces can be reintroduced, or dropped, into the game as one's own. The drop rule resembles that of shogi; the two games are often compared though no evidence suggests one developing from the other. Crazyhouse is similar to bughouse chess; however, a game of Crazyhouse involves only two players.
