Lesson
White to move. Main line: 1. Qxh7+ Kxh7 2. Rh3#
Qxh7 forces Kxh7 — there is no other legal move. Then Rh3 mates along the h-file: the bishop on c4 covers g8, the pawn on f5 covers g6, and the king’s own pawn blocks g7. Every white piece contributes exactly one square.
The rook lift (a rook sliding along the third rank to the attack file) is the classic follow-up to an h-file sacrifice. Before sacrificing, verify each escape square has a designated owner — this net uses four pieces to cover four squares.