A second important case, in which our simple calculation is of no
avail, occurs in a position where one of the defending pieces is
forced away by a threat, the evasion of which is more important
than the capture of the unit it defends. In Diagram 7, for
instance, Black may not play KtxP, because White, by playing P-
Q6, would force the Bishop to Kt4 or B1, to prevent the pawn from
Queening and the Knight would be lost. A further example of the
same type is given in Diagram 8. Here a peculiar mating threat,
which occurs not
---------------------------------------
8 | | | #B | | #Q | #R | | #K |
|---------------------------------------|
7 | | | | |#Kt | | #P | #P |
|---------------------------------------|
6 | #P |^Kt | | | | | | |
|---------------------------------------|
5 | | | ^R | |^Kt | | | |
|---------------------------------------|
4 | | | ^Q | | | | | |
|---------------------------------------|
3 | | | | | | | | |
|---------------------------------------|
2 | ^P | | | | | | ^P | ^P |
|---------------------------------------|
1 | | | | | | | ^K | |
---------------------------------------
A B C D E F G H
Diag. 8.
infrequently in practical play, keeps the Black Queen tied to her
KB2 and unavailable for the protection of the B at BI.
White wins as follows:
1. KtxB, KtxKt; 2. RxKt, QxR; 3. Kt-B7ch, K-Kt1; 4. Kt-R6 double
ch, K-R1; 5 Q-Kt8ch, RxQ; 6. Kt-B7 mate.
