On War

by Carl von Clausewitz

This geometrical alteration could only be completely carried out by tactics, and by it only through the file-march as it is called, which, with great masses, is impossible. Far less is it possible for strategy to do it. The parts which changed their geometrical relation in the old order of battle were only the centre and wings; in the new they are the divisions of the first rank corps, divisions, or even brigades, according to the organisation of the army. Now, the consequences above deduced from the new order of battle have an influence here also, for as it is no longer so necessary, as formerly, that the whole army should be assembled before action commences, therefore the greater care is taken that those troops which march together form one whole (a unit). If two divisions were so placed that one formed the reserve to the other, and that they were to advance against the enemy upon two roads, no one would think of sending a portion of each division by each of the roads, but a road would at once be assigned to each division; they would therefore march side by side, and each general of division would be left to provide a reserve for himself in case of a combat. Unity of command is much more important than the original geometrical relation; if the divisions reach their new position without a combat, they can resume their previous relations. Much less if two divisions, standing together, are to make a parallel (flank) march upon two roads should we think of placing the second line or reserve of each division on the rear road; instead of that, we should allot to each of the divisions one of the roads, and therefore during the march consider one division as forming the reserve to the other. If an army in four divisions, of which three form the front line and the fourth the reserve, is to march against the enemy in that order, then it is natural to assign a road to each of the divisions in front, and cause the reserve to follow the centre. If there are not three roads at a suitable distance apart, then we need not hesitate at once to march upon two roads, as no serious inconvenience can arise from so doing.

It is the same in the opposite case, the flank march.

Another point is the march off of columns from the right flank or left. In parallel marches (marches to a flank) the thing is plain in itself. No one would march off from the right to make a movement to the left flank. In a march to the front or rear, the order of march should properly be chosen according to the direction of the lines of roads in respect to the future line of deployment. This may also be done frequently in tactics, as its spaces are smaller, and therefore a survey of the geometrical relations can be more easily taken. In strategy it is quite impossible, and therefore although we have seen here and there a certain analogy brought over into strategy from tactics, it was mere pedantry. Formerly the whole order of march was a purely tactical affair, because the army on a march remained always an indivisible whole, and looked to nothing but a combat of the whole; yet nevertheless Schwerin, for example, when he marched off from his position near Brandeis, on the 5th of May, could not tell whether his future field of battle would be on his right or left, and on this account he was obliged to make his famous countermarch.

If an army in the old order of battle advanced against the enemy in four columns, the cavalry in the first and second lines on each wing formed the two exterior columns, the two lines of infantry composing the wings formed the two central columns. Now these columns could march off all from the right or all from the left, or the right wing from the right, the left wing from the left, or the left from the right, and the right from the left. In the latter case it would have been called “double column from the centre.” But all these forms, although they ought to have had a relation directly to the future deployment, were really all quite indifferent in that respect. When Frederick the Great entered on the battle of Leuthen, his army had been marched off by wings from the right in four columns, therefore the wonderful transition to a march off in order of battle, as described by all writers of history, was done with the greatest ease, because it happened that the king chose to attack the left wing of the Austrians; had he wanted to turn their right, he must have countermarched his army, as he did at Prague.

If these forms did not meet that object in those days, they would be mere trifling as regards it now. We know now just as little as formerly the situation of the future battle-field in reference to the road we take; and the little loss of time occasioned by marching off in inverted order is now infinitely less important than formerly. The new order of battle has further a beneficial influence in this respect, that it is now immaterial which division arrives first or which brigade is brought under fire first.

Under these circumstances the march off from the right or left is of no consequence now, otherwise than that when it is done alternately it tends to equalise the fatigue which the troops undergo. This, which is the only object, is certainly an important one for retaining both modes of marching off with large bodies.

The advance from the centre as a definite evolution naturally comes to an end on account of what has just been stated, and can only take place accidentally. An advance from the centre by one and the same column in strategy is, in point of fact, nonsense, for it supposes a double road.

The order of march belongs, moreover, more to the province of tactics than to that of strategy, for it is the division of a whole into parts, which, after the march, are once more to resume the state of a whole. As, however, in modern warfare the formal connection of the parts is not required to be constantly kept up during a march, but on the contrary, the parts during the march may become further separated, and therefore be left more to their own resources, therefore it is much easier now for independent combats to happen in which the parts have to sustain themselves, and which, therefore must be reckoned as complete combats in themselves, and on that account we have thought it necessary to say so much on the subject.

Further, an order of battle in three parts in juxtaposition being, as we have seen in the second 1 chapter of this book, the most natural where no special object predominates, from that results also that the order of march in three columns is the most natural.

It only remains to observe that the notion of a column in strategy does not found itself mainly on the line of march of one body of troops. The term is used in strategy to designate masses of troops marching on the same road on different days as well. For the division into columns is made chiefly to shorten and facilitate the march, as a small number marches quicker and more conveniently than large bodies. But this end may, be attained by marching troops on different days, as well as by marching them on different roads.