5.Bf4Not a commendable continuation, as Black cleverly demonstrates.
7…Nge7Excellent. 7) ..., Kt - B 3 would be far weaker, as the Q Kt would remain unguarded and the K B P obstructed.
13…Qe7Black is well developed and the White Q B P is weak.
16.c4Here White ought to have played for attack à tout prix. By 16) P - K B 4 he would have definitely ruined the Pawn's position, it is true, but he would have opened lines for Bishop and Rook, thus perhaps recovering the lost ground. The White position does not stand finessing, as Black has obviously the superior position, as long as White's Q B is shut out at Kt 3.
17.Qh5The intention being, after 17) ..., K R - K sq, to continue with 18) P - B 5, P x P; 19) R - Kt 7. But Black finds a far better reply.
18.Rfd1But now was the time to liberate the Q B by B x Kt, R x B; Q x P. This omission is taken advantage of by Black in masterly style.
20…Rc5Far better than R - Q B 2. If White now play P - B 4, Black can reply K R - B sq, threatening to win a piece by B x B.
23.e4White is now badly in need of the displaced Bishop. If the K B P was already at B 3, White could play B - B 2, and Black's attack would not have succeeded.
Emanuel Lasker, The International Chess Congress, St. Petersburg, 1909 (1910) · Public domain · source