en.m.wikipedia.org/wiki/Seirawan_chess
Rules- whenever a player moves a backrank piece(K,Q,B,N,R)from its starting position, if it is the first time the piece has moved during the game, the player may place either an elephant(moves like N and R) or falcon(moves like N and B) onto the square that the piece moved from.
Rules- whenever a player moves a backrank piece(K,Q,B,N,R)from its starting position, if it is the first time the piece has moved during the game, the player may place either an elephant(moves like N and R) or falcon(moves like N and B) onto the square that the piece moved from.