Castling Through Check
You are not allowed to “castle through check”. This means that the King cannot move through a square that is attacked by an enemy piece. This means that to stop a King from castling, you simply have to apply a piece against a square next to the King. Obviously, you can also attack the King directly, since Castling Out of Check is disallowed (by the ruels), and you can also attack the square where the King would end up after castling, because you obviously cannot “Castle Into Check”.
Note that the Rook can go through an attacked square. This occurs on the Queenside, where the square "b1’ or "b8’ being attacked does not prevent Queenside castling. Although it makes it pretty dangerous for the King, as an enemy piece is taking a square next to where it ends up!
Related Chess Rules Topics
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