Marie Sebag (Black) Puzzle: Win — Discovered Check

A discovered check occurs when one piece moves away from a line, uncovering a rook, bishop, or queen attack on the enemy king. In this chess endgame, the knight is attacked by a lower-value piece, but moving it creates an immediate check against the exposed king. That forcing move gains time and turns the opponent’s active rook into a hanging piece. The key idea is to combine king pressure with a direct material win.