Vienna Game Max Lange Defense Puzzle (Rated 1378): Use a Discovered Check — Win the Queen

Discovered checks are devastating in the middlegame because the checking move is free — the opponent must answer it no matter what else the moving piece achieves. In this Vienna Game, Max Lange Defense position, Black's knight blocks a checking line to White's uncastled king while sheltering the white queen. The knight sidesteps to open that line, landing on a square that attacks the queen. White must spend a move on the king, so the queen falls — a decisive material gain.