bound to yield a piece in return sooner or later. The position of
Diagram 37 is typical for cases of this kind.

+---------------------------------------+
8 | #R | | #B | #Q | | #R | #K | |
|---------------------------------------|
7 | #P | #P | #P | | | #P | #P | #P |
|---------------------------------------|
6 | | | #Kt| #P | | #Kt| | |
|---------------------------------------|
5 | | | | | #P | | ^B | |
|---------------------------------------|
4 | | #B | ^B | | ^P | | | |
|---------------------------------------|
3 | | | ^Kt| ^P | | ^Kt| | |
|---------------------------------------|
2 | ^P | ^P | ^P | | | ^P | ^P | ^P |
|---------------------------------------|
1 | ^R | | | ^Q | | ^R | ^K | |
+---------------------------------------+
a b c d e f g h

DIAGRAM 37.

Supposing Black plays (1) ..., P-h6; (2) B-h4, P-g5 to free
himself of the pinning Bishop. Then White can sacrifice the
Knight f3 for the two black Pawns and thereby maintain the pin
with the threat to regain the Knight immediately through Kt-d5.
The ensuing play could be the following: (3) Ktxg5, Pxg5; (4)
Bxg5, Bxc3; (5) Pxc3. Now White threatens to play P-f4 and Pxe5