The rules of chess
Movement of the pieces (3)
The king moves one square in any direction, horizontally, vertically, or diagonally. There is one special type of move, made by a king and rook simultaneously, called castling: see below.
The king is the most important piece of the game, and moves must be made in such a way that the king is never in check: see below.
Under certain, special rules, a king and rook can move simultaneously in a castling move.
The following conditions must be met:
- The king that makes the castling move has not yet moved in the game.
- The rook that makes the castling move has not yet moved in the game.
- The king is not in check.
- The king does not move over a square that is attacked by an enemy piece during the castling move.
- The king does not move to a square that is attacked by an enemy piece during the castling move.
- All squares between the rook and king before the castling move are empty.
When castling, the king moves two squares towards the rook, and the rook moves over the king to the next square, i.e., white's king on e1 and rook on a1 move to: king c1, rook d1 (long castling), white's king on e1 and rook on h1 move to: king g1, rook f1 (short castling), and similar for black.
position before and after castling: white short, and black long
Neither white nor black may castle: white is in check, and the black king may not move over d8
Written by Hans Bodlaender.
WWW page created: September 23, 1997.