Another 'Must Win' Game by Lasker

As I mentioned in A Fictional Account of St. Petersburg 1914, only a win in his last round game against Marshall would guarantee Lasker first place. The game was another example of the World Champion's ability to prevail in situations requiring strong nerves.

In the diagrammed position, which is already somewhat difficult for Black, Marshall played 13...g4. Kasparov gave the move '?!', and noted that 13...O-O-O 'is better'. Now Lasker played the surprising 14.Nh4. Kasparov said nothing about this move, while Soltis assigned a '!', and asked:

Why does White exile the Knight to the side of the board with no foreseeable means of getting it back into play? The answer is that only by taking away f5 does he make d4-d5 a real threat. If he had allowed, say, 14.Nd2 O-O-O 15.d5 Bf5, Black is at least equal.

In other words, the tempo that Black needed to defend with 14...d5 gave White enough time to maintain the attack against the Black Queenside.

St. Petersburg (final) 1914
Marshall, Frank James

Lasker, Emanuel
(After 13.h2-g3(xN))
[FEN "r3kb1r/pppnqp2/3pb2p/6p1/3P4/2N2NP1/PPP1QPP1/2KR1B1R b kq - 0 13"]

The game continued 15.Qb5 O-O-O 16.Qa5 a6. Now Lasker's 17.Bxa6! was probably based on intuition. After 17...bxa6 18.Qxa6+ Kb8 19.Nb5 Nb6 20.Rd3, Kasparov noted

The critical position for assessing the correctness of Lasker's combination. Several commentators considered this to be the decisive mistake, and suggested instead the immediate 20...Nc4 so as not to allow the Rook to go to b3. However, a more careful study of the position, even without the help of a computer, reveals that after 21.Rb3 Qg5+, White has two tempting continuations: 22.f4!? gxf3+ 23.Kb1 Nd2+ 24.Ka1 Nxb3+ 25.cxb3 Qxg3 26.Nxf3 Bd6 27.Rc1; [or] 22.Kb1 Nd2+ 23.Ka1 Nxb3+ 24.cxb3 Bd6 25.Qa7+ and wins.

Marshall played instead 20...Qg5+, and resigned on his 29th move. To play through the complete game see...

Emanuel Lasker vs Frank James Marshall, St Petersburg f 1914
http://www.chessgames.com/perl/chessgame?gid=1094969

...on Chessgames.com.