Mad piece

An undefended piece that chases the king without pause (or, less often, another piece), safe because capturing it would leave the opponent in stalemate. A rook most often plays the role of the "mad" piece. A combination built around a mad piece lets the side facing a loss save a draw.

Boards can be stepped through with the mouse wheel, a swipe, or the arrow keys — not just the buttons below them. Interactive boards

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2. Stalemate
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