Castling - peregrineshahin/ChessProgrammingWiki GitHub Wiki

title: Castling

Home * Chess * Moves * Castling

Marina Kalinovsky - Castling [1] Castling is a composite move of King and Rook at the same time. In standard chess it consists of moving a king two squares towards the rook and executing a jump of a rook over the king.

Rules

The prequisites for doing it are as follows:

the king and the relevant rook must not be moved, considered as castling rights inside a chess position
the king must not be in check
no square between king's start and final square may be controlled by the enemy

Irreversibility

While castling is irreversible with respect to the castling rights and resets the position index to determine repetition of positions, castling doesn't reset, but increments the halfmove clock concerning the fifty-move rule [2] [3].

Chess960

In Chess960 castling is a move reaching the position just like after standard chess castling, which may be achieved by (a) moving the king to c1 or g1 ant then executing a jump by relevant rook (b) jumping with the rook over a king already placed on c1 or g1 (c) interchanging the positions of king and rook [4].

Shogi

A formation achieved after castling is called a castle. This is often contrasted with a castle in the game of Shogi, requiring several moves to complete, but it seems wrong, since chess also has several standard defensive castle formations - like the one after fianchetto of a king's bishop or the one with a knight on g7, often achieved in the Old Benoni. For that reason it might be interesting to use shogi programming concepts of a castle map and an attack map in chess.