4.Ng5This attack may be tempting, as the B P cannot be protected, but it is against that elementary principle which says that no attack should be undertaken in the opening until the minor pieces are mobilised, provided of course that Black also has made sound opening moves. There is every likelihood that the attack in the present instance will lead to nothing. It has taken many years to find the correct reply, but now that it is known, the opening has practically disappeared from master practice. Instead of the move in the text, White can play either P—Q 3, leading almost unavoidably to a drawing variation of the Giuoco piano, or Castles which might bring about the Max Lange attack after 4...B—B 4; 5 P—Q 4, P x P.
5…Na5This is a typical position in the Two Knights' defence. The former continuation 5...Kt x Q P has long been abandoned, as the attack that White can initiate by 6 Kt x B P, K x Kt; 7 Q—B 3 ch, forcing the Black King to K 3, is dangerous, though the result is uncertain. The move in the text breaks the attack from the very first, and Black gets the advantage as he can gain time by attacking the two minor pieces which it should be noted, are unsupported, and in addition obtain a speedy development, worth more than the pawn given up for it.
6.d3B—Kt 5 ch is an alternative. The advantage is Black's in this case also—e.g. P—B 3; 7 P x P, P x P; 8 B—K 2, P—K R 3; 9 Kt—K B 3, P—K 5; 10 Kt—K 5, Q—B 2; 11 P—Q 4, B—Q 3 (or P x P e.p. followed by B—Q 3); 12 P—K B 4, P x P e.p.; 13 Kt x P, Kt—Kt 5 or 11 P—B 4, B—Q 3; 12 P—Q 4, P x P e.p.; 13 Kt x P, Castles. Black has an easy game and open lines.
10.Nfd2The Knight must move sooner or later.
12.Qf1A sorry retreat, but the plausible Q—Q 2 would be disastrous, e.g. P—K 6 !; 13 P x P, Kt—K 5 and Q—R 5 ch
12…Bb4+Black's superior development begins to tell in no uncertain fashion. Now White can neither play 13 B—Q 2 on account of B x B ch; 14 Q Kt x B, R—K 1, followed by P—K 6, nor 13 Kt B 3 on account of B x Kt; 14 P x B, P—B 3 regaining the pawn and maintaining positional advantage. White has therefore no alternative but P—B 3, which weakens his Q 3, where a Black Knight soon settles down.
15.g4At last White can castle. He can, of course, only castle on the Queen's side, because his King's side pawns are shattered. Now games in which the Kings castle on different wings are more or less beyond calculation, as pointed out before. On the whole, the player who first attacks wins. But experience has shown that the Queen's side is more difficult to defend on account of its greater expanse, and this theory is supported by the present game. In addition, White's development is not completed yet, whilst all the Black forces are ready to strike.
18…b5Storming the position with pawns is peculiar to this kind of game. The intention is to break up the opposing pawn position, and to open files for the Rooks. Pawns are cheap in such cases. Open lines for the pieces are the things that matter, and the fewer pawns there are left, the more open lines are available for the attack.
21.Ka1The King was not safe on the diagonal. White wishes to push on his King's side pawns (P—B 4—B 5, and so on). But after P x P e.p. there would be a fatal discovered check by the Black Knight.
21…Qxb5Black's advantage becomes more marked. He has recovered his pawn, and for the ensuing attacks on both sides he is better placed, having already two open files for his Rooks.
24…Qa4The position bristles with chances for daring sacrifices. After 25 Kt x B P, for instance, Black could play R x Kt !; 26 P x R, Kt—Kt 5; 27 P x Kt, P x P; 28 P—R 3 (Q—B 4 ch ?, B—B 2), B—B 3; 29 K—R 2, Q x P ch; 30 P x Q, R x P mate.
27…c5White's compulsory 25 P—Kt 3 has weakened his Q B 3, and the move in the text is intended to open the diagonal K B 3—Q B 6 for the Black Bishop.
31…Rae8White cannot parry all the threats at once. Though he gets rid of the threatening B, he lets in the hostile R on the K file and the end cannot long be delayed.
Edward Lasker, Chess Strategy (1921) · Public domain · source