Kriegspiel (chess)

Kriegspiel is a chess variant invented by Henry Michael Temple in 1899 and based upon the original Kriegsspiel, German for war game, developed by Georg von Reiswitz in 1812. Each player can see their own pieces but not those of the opponent, so a third person or a computer must act as umpire with full information about the progress of the game. Players attempt moves on their turns and the umpire declares each attempt legal or illegal; an illegal move must be retried, while a legal one stands. Each player is told about checks and captures and may ask the umpire whether any legal pawn captures exist. Because the position of the opponent's pieces is unknown, it is a game of imperfect information. On the Internet Chess Club it is called Wild 16, and it is similar to dark chess.