Marienbad System Puzzle (Rated 1678): Crush a Fork — Decisive Material Gain

This middlegame puzzle shows how active pieces can turn king safety into a decisive material gain. Black’s heavy pieces are coordinated against the white king, and the key idea is to use forcing checks to drag the king into a vulnerable square. Once the defender is overloaded, a fork becomes possible and the position collapses. The lesson is that tactical pressure often starts with activity, not immediate material.