Chess960 puzzles: Castling mate

The castling mate is the rarest gem of all: the act of castling itself delivers checkmate. Chess960 makes it far more likely than classical chess — king and rook start on unusual squares, so castling can transform the attacking geometry in one move. The sign: the enemy king stands on the line where your rook will land, with the nearby squares already covered. Treat castling as a fighting move — the only move that moves two pieces at once.