Queen's Gambit Declined Marshall Defense Puzzle (Rated 1298): Sacrifice — Win a Queen

In the middlegame, pieces often do double duty. Here Black's bishop is doing two jobs at once: it shields the enemy queen from the black queen's line of sight, yet it also reaches deep into the white king's cover. Sacrificing it with check forces the king to capture — a deflection that strips away the shield. With the blocking bishop gone, the exposed queen has no defenders and falls on the spot. A cheap-looking offering turns into a decisive material gain.