3 | | ^P | | | ^P | ^R | | |
|---------------------------------------|
2 | ^P | | | | ^Q | | ^P | ^P |
|---------------------------------------|
1 | | | | ^R | | | | ^K |
+---------------------------------------+
a b c d e f g h

DIAGRAM 29.

White plays Kt-f6+ and Black cannot go with the King into the
corner as the Rook would mate him on h7. After K-f8 White draws
the game through perpetual check; for after (2) Kt-h7+, K-e8; (3)
Kt-f6+ the King must go back to f8 as on d8 he would be mated by
R-d7. Consequently White can check the King indefinitely on h7
and f6.

An example for the cooperation of Rook and Bishop is shown in
Diagram 29. White plays B-f6, and there is no way for Black to
prevent the mate threatened through R-h3 followed by R-h8.

It is evident that the force of the Rooks will increase as the
board gets emptier through the exchange of men, for they will
then find more open lines to act in. One of the most important
lines for Rooks to occupy is--especially in the ending --the one
in which most of the attackable Pawns of the opponent are
standing, that is in the majority of cases the second or the
seventh rank respectively. If both Rooks cooperate with each
other in this rank they usually decide the victory within a short
time.