Sword Chess

Secretly arm one piece with a sword that cuts any neighbour.

Before the game each player secretly gives a sword to one knight, bishop or pawn. On your turn, move normally or swing instead. A swing removes one piece on any neighbouring square in a single hit, including the enemy king, and the sword is ready again on every later turn. If its carrier dies or gets captured, the sword remains on that square for another piece to collect (the capturer if it was a capture).