{421}
Black.
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| ^K | | #K | | | | | ^B |
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| ^Kt| | | | | | | |
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White.
FIG. 20.
[WHITE TO MOVE AND WIN.]
To checkmate with Bishop and Knight is a very difficult process. Checkmate
can only be forced if the Black King is driven to one of the Rook squares
of the same colour as the Bishop. In the position shown in Fig. 20 the
Black King must be driven either to Q R sq., or K R 8. Frequently the
Bishop and Knight are separated from the White King; in that case the Black
King cannot be prevented from moving to a Rook square of the opposite
colour to the Bishop. Then the forces must be brought together to act in
concert with the White King; when, by combined action, the Black King can
be forced on to a corner square of the same colour as White's Bishop, and
checkmated as shown in the appended solution. Mate can be forced in the
most {422} unfavourable position (see Fig. 20) in about thirty or
thirty-one moves.
WHITE. BLACK.
1. Kt to Kt 3: ch. 1. K to B 3
If 1. ... K to B 5; then 2. B to Q sq., K to B 6; 3. K to Kt 5, K to Q
6; 4. K to B 5, K to K 5; 5. B to B 2: ch., K to K 4; 6. Kt to Q 4, K
to B 3; 7. K to Q 6, K to B 2; 8. Kt to B 3, K to B 3; 9. Kt to K 5, K
to Kt 2; 10. K to K 6, and the King is gradually forced on to the last
row.
2. K to Kt 4 2. K to Q 4
3. B to B 3: ch. 3. K to Q 3
4. Kt to Q 4 4. K to K 4
5. K to B 5 5. K to B 3
6. K to Q 5 6. K to B 2
7. Kt to B 5 7. K to B 3
8. Kt to Q 6 8. K to Kt 3
9. K to K 5 9. K to Kt 2
10. B to K 4 10. K to Kt sq.
11. K to B 6 11. K to R sq.
The King is now on the Rook square of opposite colour to the Bishop, and
must be driven to K R 8, or Q R square, in order to be checkmated.
12. Kt to B 7: ch. 12. K to Kt sq.
13. B to B 5 ...
Purposely losing a move (_coup de repos_); it is immaterial where the
Bishop moves to so long as it remains on the same diagonal, the object
being to force Black to move, without altering White's position.
... 13. K to B sq.
14. B to R 7 ...