Diagram 51 shows a similar example, the only difference being that it is not the advance of the Black Knight’s Pawn but that of the Rook’s Pawn which gives White an opportunity of opening a file for his Rooks.  He will accomplish this by advancing his Knight’s Pawn to g5 and exchanging him against Black’s Rook’s Pawn.  If he does not want to play P-g4 on the first move, because Black could take the Pawn with his Knight, he can prepare the advance by R-g1.  But he need not really fear the loss of the Pawn, because in taking him Black would himself open the g-file for White’s Rook and White is sure to obtain an overwhelming attack.  It would, of course, be futile for Black to try and stop the advance of White’s g-Pawn by P-g5, as White would then simply open the Rook’s file by P-h4 and Pxg5, quite apart from the fact that he could sacrifice his Bishop e3 for two Pawns, thereby depriving Black’s King of all protection.

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

Diagram 51.

The play might proceed like this:  (1) P-g4, P-g5; (2) Bxg5, Pxg5; (3) Qxg5+, K-h8; (4) Q-h6+, K-g8; (5) P-g5, Kt-e4; (6) Ktxe4, Pxe4; (7) P-g6, Pxg6; (8) Qxg6+, K-h8; (9) R-g1, etc.

Ordinarily both players castle on the same side of the board so that neither of them can advance his Pawns in an attack against the opposing King without weakening his own King’s position.  Only if a player holds more territory and has a greater number of pieces on the King’s wing than the opponent he can embark on an attack which involves an advance of the Pawns in front of his King.  Diagram 52 offers a typical example.

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

Diagram 52.