mate in four moves through Rxg6, Qxg6, Q-h6 and R-g1 Black could
sufficiently defend himself with (8) ..., P-d5, unpinning the
Pawn f7 and enabling B-e7, which would supply the much needed
protection for the square f6. However, White can frustrate
Black's intention by playing (8) P-d4!! If Black takes with the
Pawn, (9) P-e5 follows forcing Pd6xe5 after which Black cannot
any more intercept the diagonal of the Bishop c4 so that there
remains no defense against (10) R-g1.

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

DIAGRAM 48.