Monochromatic chess
Encyclopedia
Monochromatic chess is a chess variant
Chess variant
A chess variant is a game related to, derived from or inspired by chess. The difference from chess might include one or more of the following:...

 created by Raymond Smullyan
Raymond Smullyan
Raymond Merrill Smullyan is an American mathematician, concert pianist, logician, Taoist philosopher, and magician.Born in Far Rockaway, New York, his first career was stage magic. He then earned a BSc from the University of Chicago in 1955 and his Ph.D. from Princeton University in 1959...

, in which the initial board position and all rules are the same as in regular chess, except that pieces which begin on a black square must always stay on a black square and pieces which begin on a white square must always stay on a white square. This would mean that knights
Knight (chess)
The knight is a piece in the game of chess, representing a knight . It is normally represented by a horse's head and neck. Each player starts with two knights, which begin on the row closest to the player, one square from the corner...

 can never move, but The Classified Encyclopedia of Chess Variants says that knights make a double jump. It has been suggested that a knight be replaced with a (3,1)-leaper.

If knights are allowed to move (or are captured, clearing the way), castling
Castling
Castling is a special move in the game of chess involving the king and either of the original rooks of the same color. It is the only move in chess in which a player moves two pieces at the same time. Castling consists of moving the king two squares towards a rook on the player's first rank, then...

 may become possible, but only on the kingside. Under the rules, pawns
Pawn (chess)
The pawn is the most numerous and weakest piece in the game of chess, historically representing infantry, or more particularly armed peasants or pikemen. Each player begins the game with eight pawns, one on each square of the rank immediately in front of the other pieces...

 can only move by capturing or by advancing two squares for their first move.

A stalemate
Stalemate
Stalemate is a situation in chess where the player whose turn it is to move is not in check but has no legal moves. A stalemate ends the game in a draw. Stalemate is covered in the rules of chess....

 occurs if a player's king is not in check but the player nevertheless has no legal moves under the rules of the game. Similarly, a checkmate
Checkmate
Checkmate is a situation in chess in which one player's king is threatened with capture and there is no way to meet that threat. Or, simply put, the king is under direct attack and cannot avoid being captured...

 occurs if the king is placed in check and the king has no legal moves under the rules of the game. This means that certain board positions in regular chess which would not result in the end of the game can be checkmates or stalemates in monochromatic chess. For example, each player has one bishop for which it is possible to obtain checkmate with just this bishop and a king, while it is impossible with the other bishop along with the king, since only one bishop is capable of threatening the king of the opposing side. Because the two kings must occupy squares of different colours, they are allowed to be located next to each other.

This variant is used mostly in chess problems
Fairy chess
Fairy chess comprises chess problems that differ from classical chess problems in that they are not direct mates. The term was introduced before the First World War. While selfmate dates from the Middle Age, helpmate was invented by Max Lange in the late 19th century. Thomas Dawson , pioneer of...

.
Smullyan's example asks: What color is pawn g3 - white or black? Answer is black – with white pawns on d2 and f2, the white king can move from e1 only with castling and then g1-h2-g3-... so the pawn on g3 cannot be white.

Bichromatic chess

In bichromatic chess, the opposite restrictions apply. A piece on a white square must move to a black square and vice versa. Hence pawns cannot capture (or advance two squares) and bishops cannot move. Also castling and en passant
En passant
En passant is a move in the board game of chess . It is a special pawn capture which can occur immediately after a player moves a pawn two squares forward from its starting position, and an enemy pawn could have captured it had it moved only one square forward...

are impossible, and queens behave like rooks.
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
x
OK