The position is now decisive. My queen on g5 attacks along the g5-c1 diagonal (through f4, e3, d2 — all empty) directly to the White rook on c1. White's king is on g1. When I capture the rook on c1 with Qxc1, the queen attacks along the entire 1st rank (c1→d1→e1→f1→g1). The king can only escape to f1 or h1 — but both are covered by the queen's rank attack. No White piece can block (no piece can reach d1, e1, or f1) or capture the queen on c1. This is **checkmate**.