In the majority of cases no open file is available on the wing and the attack with the Rooks is then much more difficult. There is little use in advancing the Pawns on the wing on which the hostile King has castled unless one of them can be exchanged so that a line is opened which the Rooks can occupy. As a rule such an exchange is only possible in case one of the Pawns in front of the King has moved. In the position of Diagram 50 for instance, White is able to open the h-file by advancing the h-Pawn and exchanging it against Black's g-Pawn, while Black, who would like to use his Rooks in an attack on the Queen's wing, has little hope to open a file on that side of the board. If Black's g-Pawn were still on his original square, the advance of White's h-Pawn would be of no avail. Black would simply wait until the Pawn has advanced to h6 and then he would play P-g6 so that White's own Pawn would block the h-file for the Rook. In the above position, which occurred in one of six simultaneous games played by the author in a blindfold-exhibition, the attack developed as follows: (1) (2) (3) (4) P-h4 B-b3 P-h5 Pa2xb3 P-b5 Kt-a5 Ktxb3 Q-a5
Black has succeeded in opening a line also, but he cannot get his Rooks working in it. His last move threatens mate in two moves by Q-a1; Kt-b1, Bxb2; but White simply defends himself first against this threat and then proceeds with his attack on the King's wing which is irresistible. (5) (6) (7) (8) K-b1 Pxg6 B-h6 Bxg7 Kt-c6 Pf7xg6 R-f7 Rxg7
With this exchange White has weakened the defense around Black's King who has now only the Rook and himself to rely on for protection. (9) Kt-g5 P-d5
Black opens the seventh rank in the hope that it will enable his Queen's Rook or his Queen to come to assistance. But so great is the advantage afforded White by the open h-file that he can sacrifice his Knight to break through Black's chain of defense and force the mate before Black has a chance to touch his Queen or his Rook. (10) Ktxh7 Rxh7
If Q-c7 or Ra8-a7, White continues (11) Q-h6! Rxh7?; (12) Qxg6+, K-h8; (13) Q-e8+, K-g7; (14) Rxh7+, Kxh7; (15) R-h1+, etc.
(11) (12) (13) (14) (15) (16) (17) (18) (19) (20) (21)
Rxh7 R-h1+ Q-h6+ Q-h7+ Q-h8+ R-h7+ Q-f8+ P-f4+ Q-f6+ R-h3+ Q-h4
Kxh7 K-g7 K-f7 K-f6 K-e7 K-d6 K-e5 K-d4 K-e3 K-d2
and Black resigns as there is no defense against Q-f2. 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.