to c5.

However, in the position resulting after these moves (Diagram 47)
White gets the upper hand because he is one move ahead in the
attack on the opposing King's Knight. The danger of the
concentration of two pieces on this Knight lies in the fact that
Black is obliged to retake with the g-Pawn in case White
exchanges on f6 and that thereby the squares f6 and h6 lose their
natural protection.

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

DIAGRAM 47.