The position is an excellent example of how logical thinking translates into a series of moves. Capablanca wrote,
This position should be carefully studied. It is evident to White that Black wants to play 20...Nd7 followed by 21...Ne5 or 21...Nc5 and 22...Na4, forcing the advance of the b-Pawn in some cases, and then through the combined action of the Bishop at f6, the Pawn at d4, and the Knight ultimately at c3, cramp White's game so as to make it impossible for him to hold out.
It is against this plan that White must evolve another that will meet it at every point. If this can be done, then White must come out on top, as he will be able in the long run to concentrate sufficient forces against the Pawn at d4 or the Pawn at b5, and take either one or the other. The text will show how this is done.
St. Petersburg 1913
Dus-Chotimirsky, Fyodor
Capablanca, Jose Raul
(After 19...a6-b5(xP))
[FEN "2r2rk1/4bppp/1q1p1n2/1p1P4/3pP1b1/3B1N2/1P3PPP/R2QRNK1 w - - 0 20"]
The Cuban continued 20.h3! (all '!'s are from his notes), and after 20...Bxf3 21.Qxf3 Nd7 22.Rec1! Nc5, noted,
White has not only led on Black to this maneuver, but what is more he will now induce him to go on with 23...Na4.He did this with 23.b4! Na4. Capablanca:
While this game was being played there were present, besides masters of lesser rank, two of the leading players of the world, and they thought I had allowed my opponent to obtain a winning position. They had not seen my 25th move, which was to turn the tide of the battle. Had now Black played 23...Nxd3 then 24.Qxd3 Rc3? 25.Rxc3 dxc3 26.Ne3 Bf6 27.Nc2 followed by 28.Ra5 and White has the better game. Probably the best line of play for Black would be: 23...Nxd3 24.Qxd3 Bf6.
Kasparov agreed with this last line and continued, 'the sacrifice of the b-Pawn would have led to an unclear game: 25.Rxc8 Rxc8 26.Ra5 Qc7 27.Qxb5 g6.
After 24.Rxc8 Rxc8, Capablanca played the powerful 24th move mentioned in the last note: 25.e5!. Kasparov also gave the move a '!', but wrote, 'I don't understand why it was thought that Black had a 'winning position': even after the dull 25.Ng3 nothing bad for White is apparent.' One wonders what Capablanca's colleagues were thinking.
Black tried to defend with 25...g6, which Capablanca considered inevitable:
White threatened 26.Qf5. Had Black played 25...Rf8, he would later on be forced to play 26...g6.The game continued 26.e6 Rf8 27.Ng3! Qb7. Capablanca:
If 27...fxe6 28.Qg4 threatening both 29.Bxg6 and also 29.Qxe6+.
Now White finished powerfully with 28.Nf5! fxe6. Capablanca:
28...Kh8 was best, but then 29.Qe4 should win. Black has been wanting to take this Pawn all the time, and thinks the time has come, but it only hastens the result.
After 29.dxe6 Qc7 30.Qc6!, Black resigned a few moves later. To play through the complete game see...
Jose Raul Capablanca vs Fyodor Ivanovich Dus Chotimirsky, St Petersburg exhibition 1913
http://www.chessgames.com/perl/chessgame?gid=1294504
...on Chessgames.com.