It is evident that such a sudden change of direction of a line of retreat, which is very practicable in a spacious country, ensures remarkable advantages.
1. It makes it impossible for the enemy (the advancing force) to maintain his old line of communication: but the organisation of a new one is always a difficult matter, in addition to which the change is made gradually, therefore, probably, he has to try more than one new line.
2. If both parties in this manner approach the frontier again; the position of the aggressor no longer covers his conquests, and he must in all probability give them up.
Russia with its enormous dimensions, is a country in which two armies might in this manner regularly play at prisoners’ base (Zeck jagen).
But such a change of the line of retreat is also possible in smaller countries, when other circumstances are favourable, which can only be judged of in each individual case, according to its different relations.
When the direction in which the enemy is to be drawn into the country is once fixed upon, then it follows of itself that our principal army should take that direction, for otherwise the enemy would not advance in that direction, and if he even did we should not then be able to impose upon him all the conditions above supposed. The question then only remains whether we shall take this direction with our forces undivided, or whether considerable portions should spread out laterally and therefore give the retreat a divergent (eccentric) form.
To this we answer that this latter form in itself is to be rejected.
1. Because it divides our forces, whilst their concentration on one point is just one of the chief difficulties for the enemy.
2. Because the enemy gets the advantage of operating on interior lines, can remain more concentrated than we are, consequently can appear in so much the greater force at any one point. Now certainly this superiority is less to be dreaded when we are following a system of constantly giving way; but the very condition of this constantly yielding, is always to continue formidable to the enemy and not to allow him to beat us in detail, which might easily happen. A further object of such a retreat, is to bring our principal force by degrees to a superiority of numbers, and with this superiority to give a decisive blow, but that by a partition of forces would become an uncertainty.
3. Because as a general rule the concentric (convergent) action against the enemy is not adapted to the weaker forces.