Kingside castling

In standard chess, kingside castling is castling toward the kingside, where the rook that begins closest to the king is located. It counts as one move even though two pieces change squares.

Using the square names of algebraic notation, the standard letter-and-number labeling of the board, White moves the king from e1 to g1 and the rook from h1 to f1. Black moves the king from e8 to g8 and the rook from h8 to f8.

Conditions

• The king must still be on its starting square and must never have moved earlier in the game.
• The original kingside rook must still be on its starting square and must never have moved earlier in the game.
• No piece may stand between the king and that rook.
• The king cannot be in check, cross an attacked square, or finish on an attacked square.

The rook itself may be attacked because the attack restrictions concern the king's squares. Kingside castling often moves the king away from the center and activates the rook quickly, but the choice still depends on the current position: legality does not guarantee that castling is best.