French Defense Marshall Gambit Mate In 1 Puzzle (Rated 1010): Spot Mate in 1 — French Defense
This middlegame puzzle comes from a sharp French Defense structure where one side’s king is exposed and the queen can deliver a direct finish. The key idea is recognizing when a checking move is also a mating move because the king has no safe escape squares and the defending pieces cannot interpose or capture. Even in a materially complex position, a single forcing move can outweigh everything else when the enemy king is boxed in.