13. ...  B-K3 14.  RxP Castles 15.  PxP P-B5 16.  B-R2

Now the Bishop is hemmed in permanently; in other words, Black is a piece up and must win easily.  Therefore 16.  B-R4 was compulsory in order to get at any rate three pawns for the piece, thus:  16. ...  B-Q2; 17.  QxP, RxR; 18.  PxR, BxB; 19.  QxP.

16. ...  RxR 17.  PxR Q-R4 18.  B-Kt1 P-B6 19.  Q-Kt3

White tries to work up an attack on the King’s side while Black is still occupied on the other wing.

19. ...  R-B1 20.  P-B4 B-KB4 21.  R-K1 B-B3 22.  K-R1

In order to answer BxQP by 23.  B-K3 and P-R7, 22. ...  QxP is not feasible because of QxP.

22. ...  P-R3 23.  P-R3 R-Kt1 24.  B-K3 QxP 25.  R-Q1 Q-R8 26.  Q-K1

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

Diag. 121

The sequel forms an instructive example of how superior development can afford winning chances even when there is no immediate prospect of material gain.  The opposing pieces are gradually constricted until the defending lines are weakened by compulsory pawn moves.  In the present position Black quietly sets to work to bring his Bishops to bear on the White King.

26. ...  B-K5
27.  K-R2 B-K2
28.  Q-B1

to free his game somewhat with P-B5, which Black prevents at once.

28. ...                 P-B4
29.  R-K1               B-R5

Being probably short of time, Black makes a few irrelevant moves.  If his aim was not the opening of the KKt file but the subsequent sacrifice of the Queen, he might have played Q-Kt7 at once, followed by Q-Kt4.

30.  P-Kt3 B-K2 31.  B-B2 B-Q3 32.  R-B1 K-R2 33.  R-K1 R-Kt3 34.  R-B1 B-R6 35.  R-K1 Q-Kt7 36.  Q-K2 R-Kt5 37.  R-Kt1 R-Kt3

Otherwise White might embark upon a counter attack, beginning with P-Kt4.  Now this is impossible on account of R-Kt3.