occupy e5. (2) ..., K-c5; (3) R-e5; K-d6; (4) K-d4, K-c6; (5) R-
d5, K-b6; (6) R-c5, K-b7; (7) K-d5, K-b6; (8) K-d6, K-b7; (9) R-
b5, K-a6; (10) K-c6, K-a7; (11) K-c7, K-a6; (12) R-h5, K-a7; (13)
R-a5 mate.

The two examples discussed show that it is not necessary to drive
the King into the corner but that he can be mated on any square
of the edge by Queen or Rook. It will be observed that in the
mating position three of the six squares at Black's disposal are
controlled by White's King and the other three by the Rook (or
the Queen). If White had only a Bishop or a Knight in addition to
the King he could never mate Black, for neither Bishop nor Knight
can attack the King and at the same time control a square
adjacent to the King. This, however, is at least necessary to
force the mate, even in the most unfavorable position of the
King, that is, in the corner.

+---------------------------------------+
8 | | | | | | | | |
|---------------------------------------|
7 | | | | | | | | |
|---------------------------------------|
6 | ^Kt| | | | | | | |
|---------------------------------------|
5 | | | | | | | | |
|---------------------------------------|
4 | | | | | | | | |
|---------------------------------------|
3 | | | | | | | | #P |
|---------------------------------------|