Narrowness

This chess variant is one of those where many pieces occupy all places on the board.

The object of the game is to mate or to capture both kings of the opponent.

Rules:

The game is conducted by the rules of orthodox chess with the following changes:

• Promotion. When pawns reach the last rank they can promote to queen, rook, knight, or bishop.
• Check. At the will of the player one of the his kings can remain in check, and the game continues. The opponent can at will then take this king or not. If both kings of a player are in check, he is obliged to remove check for at least one king in the following turn.