-A
+A

In the first instance (I), the White Column of Attack has the advantage and the Black formation has the disadvantage; in the second case (II), this condition is reversed.

COLUMN OF SUPPORT

A Column of Support has the superiority in position, as compared with the adverse Column of Support, whenever it contains more than the latter of the following advantages, viz.:

The relative advantage and disadvantage of one Column of Support, over the opposing Column of Support, is expressed by the second term of the Strategic Syllogism, thus:

(I.)

+S
-S

or