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. In this game, each player can see their own pieces but not those of their opponent. For this reason, it is necessary to have a third person (or computer) act as an umpire, with full information about the progress of the game. Players attempt to move on their turns, and the umpire declares their attempts 'legal' or 'illegal'. If the move is illegal, the player tries again; if it is legal, that move stands. Each player is given information about checks and . They may also ask the umpire if there are any legal captures with a pawn. Since the position of the opponent's pieces is unknown, Kriegspiel is a game of imperfect information. On the Internet Chess Club, Kriegspiel is called Wild 16. Rules There are several different for Kriegspiel. The rules offered on the Chess Variant Pages are as follows. The game is played with three boards, one for each player; the third is for the umpire (and spectators). Each opponent knows the exact position of just their own pieces, and does not know where the opponent's pieces are (but can keep track of how many there are). Only the umpire knows the position of the game. The game proceeds in the following way: The umpire announces: "White [or Black] to move". "Pawn gone", when a pawn is captured. The square of the capture is announced, e.g. "Pawn gone on d4", or "Pawn captured on d4". (En passant captures are specifically announced as such, e.g. "Black has taken en passant on f3.") "Piece gone", when a piece is captured. The square of the capture is announced. "No", when the attempted move is illegal, given the opponent's position. For example: moving the king into check; moving a queen, rook, bishop, or pawn through squares occupied by the opponent's pieces; advancing a pawn into a square occupied by the opponent's pieces; moving a piece under an absolute pin. "Hell no" (or "Impossible" or "Nonsense"), when the attempted move is always illegal regardless of the opponent's position. For example, moving a bishop as if it were a knight. "Check on the vertical". "Check on the horizontal". "Check on the long diagonal" (the longer of the two diagonals, from the king's point of