(20) Ktxd2 o-o-o (21) Kt-c4
White cannot play R-d1 on account of R-d4, threatening Rh8-d8.
(21) … Bxe4 (22) Rf1-c1
This merely drives the Black King to a safe place. Ktxa5 was indicated. R-d2 could then have been answered by (23) R-c1+ and (24) R-C4.
(22) … K-b8 (23) P-f3
Again a move which helps the opponent as it drives the Bishop where he wants to go.
(23)… B-d5 (24) Ktxa5 R-c8 (25) P-b3
This situation furnishes an instructive example of the importance of the rules governing Pawn formations as previously discussed. By attacking the Knight with the King Black can force the exchange of the Bishop for the Knight on c4.
+———————————————————-+
8 | | #K | #R | | | | | #R |
|———————————————————-|
7 | | #P | | | | #P | #P | #P |
|———————————————————-|
6 | | | | | #P | | | |
|———————————————————-|
5 | ^Kt| | | #B | | | | |
|———————————————————-|
4 | | | | | | | | |
|———————————————————-|
3 | | ^P | | | | ^P | | |
|———————————————————-|
2 | ^P | | | | | | ^P | ^P |
|———————————————————-|
1 | ^R | | ^R | | | | ^K | |
+———————————————————-+
a b c d e f g h