Frank Marshall v Emanuel Lasker, world title match, New York 1907. Marshall, US champion for 27 years, is a rook up here, but his king is in danger. His idea is to meet Black’s obvious Rh4+ by Qxh4. Lasker can try 1 ... g5 to shut out the white queen and menace Rh4 mate, but then White starts a series of checks by 2 Qd7+ or 2 Qe7+ when the black king is caught in perpetual check or his rook has to withdraw from its strong position. Lasker was also a 27-year champion, but he held the world title and he soon spotted the flaw in Marshall’s defence strategy. Can you find Lasker’s next few turns which forced Marshall to resign?