The fundamental principle requires, even when the forces are equal, that the front be less extensive than the enemy's,—especially if the front remains unchanged for some time. If your strategic positions are more closely connected than the enemy's, you can concentrate more rapidly and more easily than he can, and in this way the fundamental principle will be applied. If your positions are interior and central, the enemy cannot concentrate except by passing by the mass of your divisions or by moving in a circle around them: he is then exactly in a condition not to be able to apply the fundamental principle, while it is your most obvious measure.
But if you are very weak and the enemy very strong, a central position, that may be surrounded on all sides by forces superior at every point, is untenable, unless the enemy's corps are very far separated from each other, as was the case with the allied armies in the Seven Years' War; or unless the central zone has a natural barrier on one or two of its sides, like the Rhine, the Danube, or the Alps, which would prevent the enemy from using his forces simultaneously. In case of great numerical inferiority it is, nevertheless, wiser to maneuver upon one of the extremities than upon the center of the enemy's line, especially if his masses are sufficiently near to be dangerous to you.
It was stated above that strategy, besides indicating the decisive points of a theater of war, requires two things:—1st, that the principal mass of the force be moved against fractions of the enemy's, to attack them in succession; 2d, that the best direction of movement be adopted,—that is to say, one leading straight to the decisive points already known, and afterward upon secondary points.
To illustrate these immutable principles of strategy, I will give a sketch of the operations of the French at the close of 1793. (See Plate III.)