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

DIAGRAM 40.

The Pawn f7 would then be three times attacked and three times
protected so that White cannot take him as now the pin of the
Rook resulting from Ktxf7, Ktxf7; Qxf7, Rxf7 does not lead to
anything, the square e8 being protected by the Queen. However,
White can force the win by (2) Ra1- e1, threatening again the
sacrifice of f7, as he now controls the square e8 twice. If Black
replies (2) ..., Q-f6, protecting f7 for the fourth time and
thereby making impossible White's sacrifice on that point, White