Learn How to Spot Mate in 1: Queen's Gambit Declined

This puzzle comes from the Queen's Gambit Declined and shows a classic middlegame mating net where the enemy king is left with too little room and too many loose pieces. The key idea is to notice when a queen can invade on the back rank or near the king while defenders are overloaded. Even in a materially balanced-looking position, one tactical shot can end the game immediately because the king has no safe escape squares.