For the 39th birthday of his brother Hans, Maarten Bodlaender designed a chess variant, and wrote a program that played the chess variant. The variant was designed such that it would not be hard to make a program that plays the variant well. Indeed, color chess fits well this description, and on a fast machine with a high level, the program is hard to beat. The game is played on a board formed by a 6 by 6 colored grid, with a three by one part at the right of it.
Squares have one of five colors.
Pieces move like in chess, except kings cannot leave the small three by one part, and knights are the only pieces that can change parts. Pawns do have the possibility to make a double move but cannot make an en passant capture. Kings are normal pieces, and can be moved into check and taken as any other piece. In addition, the colors of the squares determine with what kind of piece the player must move next. Each color has a piece sequence attached to it, e.g., purple has Knight, Pawn, King.