5…Qf6The threat Kt x Kt and B x B must be met in some way. P—Q 3 is not satisfactory, for Black remains with a trebled pawn after the double exchange. An alternative to the text move is B—Kt 3. Q—B 3, however, has the advantage of developing a piece, and although it is the Queen, White has no early opportunity of driving the same off, such as he often obtains when the Queen comes out so soon in the game.
7.Nc2In order to develop the Q Kt.
7…b6Out of three possible moves, Lasker selects the one which contributes most to development. B—Kt 3 does nothing in that direction, and B x B would bring the Black Knight further into play. The text move prepares the development of the B at Kt 2 with the option of Castles Q R. If White exchanges Bishops he gives up the command of his Q 4. Black's P—Q 3 might have had the same result, but then the exchange would have given White a majority of pawns on the K side, whilst White's three Q side pawns would have held the black Q side pawns, one of the latter being doubled.
8…Qg6The exchange of Bishops allows White to play Kt—K 3, thus avoiding the weakening move P—K Kt 3. 9 B—K B 4 is answered by P—Q 4 !.
12.Bc4To prevent Black's P—B 4. At first sight it seems as if the Q B P ought to move to B 4, as the advance of the Q Kt P has weakened it. But White dares not allow a Black Knight to settle at Q 5.
13.f4Black threatens to play K—R 1 in order to play P—B 4. White's position would then be very bad, and therefore he rightly decides to anticipate the move, even at the cost of a pawn. In order to gain the Q B P Black must waste a number of moves with the Q, and White gains time for a King's side attack. The pawn sacrifice is very promising indeed.
15.Rf3There seem to be many threats here, and the position is a difficult one to fathom. After disentangling his Queen, Black tries very hard to force his P—B 4. As soon as he succeeds in this he has a won game, for the open file is available both for defence and counter-attack.
18…Qb2Q—B 3 is impossible apart from the fact that it would block the K B P, e.g. 18...Q—B 3; 19 P—K 5, P x P; 20 Kt—K 4, etc.
19.Rc2Now the attack shown in the last note could be answered with Q—R 5.
20.Ng4Here P—K Kt 4 could be answered by Kt—Q 5, e.g. 21 P—Kt 5, Q—Kt 3; 22 R—Kt 3, P—B 4.
24…Nb4This prevents the Rook from occupying the Q file which is about to be opened.
26…Qd7If now Q x P, Black plays R—B 2 with unanswerable threats of R—K 1 or Q 1.
37…Nd3Threatens mate in six.
38…Ne1Mate is again threatened.
47.Rc6A few more moves “ for fun.”
Edward Lasker, Chess Strategy (1921) · Public domain · source