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 (including pawns), and squares where these pieces could move.

	a	b	c	d	e	f	g	h
8									8
7									7
6									6
5									5
4									4
3									3
2									2
1									1
	a	b	c	d	e	f	g	h

A game of Dark chess in progress; squares indicated by "×" can not be seen by the white player.

Rules

The goal of this chess variant is not to checkmate the king, but to capture it. A player isn't 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.

En passant capture is allowed, even if you do not see that it is possible. Unlike standard chess, castling is allowed even out of check, into check and through the positions attacked by opponent pieces.

This chess variant is best played on one of the online chess servers. For playing over-the-board, three chess sets and a referee are needed, just as in Kriegspiel.

There are some minor differences in the rules on different servers:

• BrainKing: pawn promotions remain unknown for the opponent.
• ItsYourTurn: the opponent knows that a pawn was promoted, but does not know where.
• SchemingMind: you do not see what is in front of your pawns, but know if the position is occupied or not.
• AjaxPlay.Com: En passant capture is not allowed; pawn promotions remain unknown for the opponent.

Variations

SchemingMind also provides some more variations of dark chess:

• Dark chess (checkmate) - you are notified that your king is in check and you can't move your king into check. The goal in this variation is the same as in standard chess - to checkmate the king.
• Dark crazyhouse - combination of crazyhouse and dark chess.
• Dark suicide - combination of suicide and dark chess.
• Sun Tzu chess - combination of Double Fischer Random Chess (like Chess960, but with different positions for white and black), crazyhouse and dark chess. You can drop pieces you have in any possible square on the board (like crazyhouse). This chess variant was invented in 2005 by John Kipling Lewis.
• Lao Tzu chess - like Sun Tzu, but you can only drop pieces on square you can see. Also invented in 2005 by John Kipling Lewis.
• Generally, because basic Dark chess rules are universal with respect to its “parent” classical variant, any other 2-player chess variant like Omega Chess, Seirawan chess or others may be played “in dark”, for example - Dark Omega Chess.^[1]

Gameplay

Dark chess has a strong strategic flavor. Planning and strategy, as well as some psychological reasoning, are very important; tactics and move searching are not.

In this chess variant a king should be carefully protected from very dangerous checks by invisible pieces. For a queen the most dangerous pieces are knights, which can attack it without becoming visible.

See also

• Fog of war

References

1. ^ Dark Omega Chess at GamesByEmail.com

External links

• Dark Chess Strategy guide
• Darkness chess by Jens Bæk Nielsen
• Online turn-based dark chess
• Dark Chess implementation for Zillions of games.
• Freeware Windows Dark Chess game called SearchAndDestroyChess.
• KIKAItachi chess supports playing Dark chess variant among others.
• www.darkchess.com Dark Chess Helper application