13. ...           KtxBch
14.  QxKt         R-K1

If now a general exchange takes place after P-Q4, the KP is lost through B-Q4.

15.  Kt-R4

White’s counter attack on the King’s side becomes threatening, and Black must continue his operations on the Queen’s wing with the greatest care, as he may be called upon at any time to concentrate his pieces for the defence of the King’s wing.

15. ...  B-KB1 16.  Kt-B5 K-R1 17.  P-KKt4 Q-Q2 18.  Kt-B2 P-QR4

Black wishes to open up files on the Queen’s side.

19.  P-QR3

Freeing the QR.

19. ...  P-QKt4 20.  QR-Q1 QR-Kt1 21.  R-Q2 P-Kt5 22.  RPxP RPxP 23.  P-B4 R-R1 24.  Q-B3 R-R7

Before trying to push home his advantage on the Queen’s side, which is made possible by the weakness of White’s QP, Black should look after his King’s side, where White has collected an alarming array of forces.  After the text move the Rook is quite out of play.

25.  P-Kt5 P-Kt3?

---------------------------------------
8 |    |    |    |    | #R | #B |    | #K |
|---------------------------------------|
7 |    |    |    | #Q |    |    |    | #P |
|---------------------------------------|
6 |    |    | #Kt|    | #B | #P | #P |    |
|---------------------------------------|
5 |    |    | #P |    | #P | ^Kt| ^P |    |
|---------------------------------------|
4 |    | #P | ^P |    | ^P |    |    |    |
|---------------------------------------|
3 |    |    |    | ^P | ^B | ^Q |    |    |
|---------------------------------------|
2 | #R | ^P |    | ^R |    | ^Kt|    | ^P |
|---------------------------------------|
1 |    |    |    |    |    | ^R | ^K |    |
---------------------------------------
A    B    C    D    E    F    G    H

Diag. 167

Black should simply play PxP with the following continuation:  26.  BxP, Kt-Q5; 27.  KtxKt, QxKt; 28.  B-K3, Q-Q3.  After the move in the text, White’s attack is overwhelming.

26.  Kt-Kt4!

White obtains a Rook and two pawns for his two Knights; this is in itself an equivalent of material.  In the present instance the exchange is of decisive advantage for White, as Black must lose several moves to bring up his Rook for the defence of his unguarded King.

26. ...        PxKt
27.  KtxBP     Kt-Q5

If PxP, White wins by 28.  Q-R5, Q-B2; 29.  P-Kt6, QxPch; 30.  QxQ and KtxR.

28.  Q-B2 Q-B3 29.  KtxR QxKt 30.  BxKt KPxB 31.  PxP B-Q2 32.  R-K1 Q-B2 33.  Q-R4!  R-R1

Not BxP because of 34.  R-KB2, followed by KR-KB sq.

          34.  R-KB2 B-B3
          35.  Q-Kt4

The threat is to open the Rook’s file by P-Kt6 with an attack on the King by the Rooks.

35. ...        R-K1
36.  RxR       QxR

BxR in order to play Q-R4 might be better.  With the Queens off the board, Black has winning chances on account of his two Bishops.  But then White might evade the exchange and proceed to seize the King’s file with the Rook after 37.  Q-B4.