How a king castles in chess

  Together with a rook, the king may make a special move called castling. To castle, the king is moved two squares in the direction of the rook, while the rook is moved to the square the king 'jumped' over.  The following diagram should help clarify things.

The arrows show where the White pieces need to go for kingside and queenside castling, while the Black pieces show the positions after castling. The king moves two squares either way.

Castling is legal only if all the following conditions are met:

1. There are no pieces between the king and rook.
2. Both the king and the rook stand on their original squares and neither has moved during the game.
3. The king is not in check.
4. The king cannot pass through check, nor into check.

Click here to test and reinforce your knowledge of castling rules.