8
7
6
5
4
3
2
1
	a	b	c	d	e	f	g	h

BLACK RESIGNED AFTER WHITE'S NEXT MOVE

Tigran Petrosian (White), the then world champion, was playing against
Boris Spassky (Black), a future world champion.

Black had been attacking the White King for a long time, but White
fought back to reach the position in the diagram.

Petrosian then played: 1.Qh8ch!!  and Spassky resigned immediately.

Black's next move is forced. He must take the Queen sacrifice: 1..... Kxh8.
It's his only move to get out of check.

White then plays: 2.Nxf7ch  capturing the Black Rook and simultaneously
attacking the Black King (now on h8) and the Black Queen on g5.

WHY DID SPASSKY RESIGN?

The Black King must move to g7 or g8 (to get out of check) allowing
White to capture the Black Queen with: 3.Nxg5.

This leaves White with two Knights to Black's one - a winning position.