11. Q-K2
White should have prevented the further advance of the Black RP by 11. P-QR4. This would have been sound policy in any case, as the R file could not have been forced open for the Black Rooks.
11. … P-R5 12. Kt-Q2 PxP
Premature. The capture is only of value if the file can be held. To that end it is first necessary to play B-Kt2 and to occupy the R file with Rooks and Queen. After the exchange of Rooks, Black is at a disadvantage for the end-game because of the inefficiency of the QB.
Diag. 165
If instead of the text move Black had driven off the Bishop to B1 with P-R6 (13. B-B3?, P-Q5!; 14. PxP, Kt-Q4) he could have enforced his P-K4, but in the long run White would have captured the QRP, and remained with a passed pawn on the R file, a powerful weapon for the end-game, e.g. l2. … P-R6; 13. B-B1, Kt-Q2; 14. KtxKt, BxKt; 15. P-K4, P-KB3; 16. P-B4, followed by Kt-Kt1.
13. RPxP RxR 14. RxR B-Kt2 15. P-KKt4
The Black pieces being cut off from the K side, White is free to attack.
15. … R-R1 16. RxRch BxR 17. P-Kt5 Kt-Q2 18. Q Kt-B3 KtxKt 19. BxKt Q-R4 20. P-B4