Transcendental Chess of one side can be any of 4²×6!÷2² = 2880. There is no castling. On the first turn a player, instead of making a move, can transpose any of two pieces on the back row. In Chess960 the back rows are mirror images, but in Transcendental Chess the setup of black and white is different 2879 out of every 2880 times (there being a 1–in–2880 chance that both sides will draw the same setup). This can create inequalities in the position. One way to equalize these inequalities is to play a couplet: the players play two games, one each as
Dark chess Dark chess Dark chess is a chess variant with incomplete information, similar to Kriegspiel. It was invented by Jens Bæk Nielsen and Torben Osted in 1989. A player does not see the entire board, only their own pieces and the squares that they can legally move to. The goal of this chess variant is not to checkmate the king, but to capture it. A player is not told if their king is in check. Failing to move out of check, or moving into check, are both legal, and can obviously result in a capture and loss of the game. Each