Stonewall Attack Puzzle (Rated 846): Skewer — Decisive Material Gain
This middlegame puzzle is a classic example of a skewer leading to decisive material gain. White’s queen is active in the enemy camp and the black king’s pieces are awkwardly coordinated, so one forcing capture can open a line with check. The key idea is that a higher-value piece is forced to move or be exchanged, exposing a more valuable target behind it. In practical classical chess, these patterns often appear when the king, queen, and rook line up on the same file.