Kriegspiel (chess) illegal, the player tries again; if it is legal, that move stands. Each player is given information about checks and captures. They may also ask the referee if there are any legal captures with a pawn. Since the position of the opponent's pieces is unknown, Kriegspiel is not a game with perfect information. As each player cannot see his opponent's pieces, the game is sometimes referred to as "blind chess". There are several different rule sets for Kriegspiel. The most widespread rules are those used on the Internet Chess Club, where Kriegspiel is called "Wild 16". The rules are as
Chess boxing an alternative to traditional roles. A chessboxing fight consists of 11 rounds, 6 rounds of chess and 5 rounds of boxing, and a victory in either chess or boxing wins and ends the entire contest. Chess and boxing rounds alternate, a full-distance contest begins and ends with a round of chess. Each round lasts three minutes, regardless of whether it involves chess or boxing. A single chess game is played over the six chess rounds. These total 18 minutes; each player is subject to a time control of 9 minutes with no increment to make all their moves (blitz chess).