Front Page Titles (by Subject) CHAPTER X: MARCHES - On War, vol. 2
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CHAPTER X: MARCHES - Carl von Clausewitz, On War, vol. 2 
On War, trans. Col. J.J. Graham. New and Revised edition with Introduction and Notes by Col. F.N. Maude, in Three Volumes (London: Kegan Paul, Trench, Trubner & C., 1918). Vol. 2.
Part of: On War
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Marches are a mere passage from one position to another under two primary conditions.
The first, is the due care of the troops, so that no forces shall be squandered uselessly when they might be usefully employed; the second, is precision in the movements, so that they may fit exactly. If we marched 100,000 men in one single column, that is, upon one road without intervals of time, the rear of the column would never arrive at the proposed destination on the same day with the head of the column; we must either advance at an unusually slow pace, or the mass would, like a thread of water, disperse itself in drops; and this dispersion, together with the excessive exertion laid upon those in rear owing to the length of the column, would soon throw everything into confusion.
If from this extreme we take the opposite direction, we find that the smaller the mass of troops in one column the greater the ease and precision with which the march can be performed. The result of this is the need of a division quite irrespective of that division of an Army in separate parts which belongs to its position; therefore, although the division into columns of march originates in the strategic disposition in general, it does not do so in every particular case. A great mass which is to be concentrated at any one point must necessarily be divided for the march. But even if a disposition of the Army in separate parts causes a march in separate divisions, sometimes the conditions of the primitive disposition, sometimes those of the march, are paramount. For instance, if the disposition of the troops is one made merely for rest, one in which a battle is not expected, then the conditions of the march predominate, and these conditions are chiefly the choice of good, well-frequented roads. Keeping in view this difference, we choose a road in the one case on account of the quarters and camping ground, in the other we take the quarters and camps such as they are, on account of the road. When a battle is expected, and everything depends on our reaching a particular point with a mass of troops, then we should think nothing of getting to that point by even the worst by-roads, if necessary; if, on the other hand, we are still on the journey to the theatre of War, then the nearest great roads are selected for the columns, and we look out for the best quarters and camps that can be got near them.
Whether the march is of the one kind or the other, if there is even a possibility of a combat, it is an invariable rule in the modern Art of War to organise the columns so that the mass of troops composing each column is fit of itself to engage in an independent combat. This condition is satisfied by the combination of the three arms, by an organised subdivision of the whole, and by the appointment of a competent Commander. Marches, therefore, have been the chief cause of the new order of battle, and they profit most by it.
When in the middle of the eighteenth century, especially in the theatre of War in which Frederick II. was engaged, Generals began to look upon movement as a principle belonging to fighting, and to think of gaining the victory by the effect of unexpected movements, the want of an organised order of battle caused the most complicated and laborious evolutions on a march. In carrying out a movement near the enemy, an Army ought to be always ready to fight; but at that time they were never ready to fight unless the whole Army was collectively present, because nothing less than the Army constituted a complete whole. In a march to a flank, the second line, in order to be always at the regulated distance, that is about a mile from the first, had to march up hill and down dale, which demanded immense exertion, as well as a great stock of local knowledge; for where can one find two good roads running parallel at a distance of a mile from each other? The cavalry on the wings had to encounter the same difficulties when the march was direct to the front. There was further difficulty with the artillery, which required a road for itself, protected by infantry; for the lines of infantry required to be continuous lines, and the artillery increased the length of their already long trailing columns still more, and threw all their regulated distances into disorder. It is only necessary to read the dispositions for marches in Tempelhof’s “History of the Seven Years’ War,” to be satisfied of all these incidents and of the restraints thus imposed on the action of War.
But since then the modern Art of War has subdivided Armies on a regular principle, so that each of the principal parts forms in itself a complete whole, of small proportions, but capable of acting in battle precisely like the great whole, except in one respect, which is, that the duration of its action must be shorter. The consequence of this change is, that even when it is intended that the whole force should take part in a battle, it is no longer necessary to have the columns so close to each other that they may unite before the commencement of the combat; it is sufficient now if the concentration takes place in the course of the action.
The smaller a body of troops the more easily it can be moved, and therefore the less it requires that subdivision which is not a result of the separate disposition, but of the unwieldiness of the mass. A small body, therefore, can march upon one road, and if it is to advance on several lines it easily finds roads near each other which are as good as it requires. The greater the mass the greater becomes the necessity for subdividing, the greater becomes the number of columns, and the want of made roads, or even great high roads, consequently also the distance of the columns from each other. Now the danger of this subdivision is—arithmetically expressed—in an inverse ratio to the necessity for it. The smaller the parts are, the more readily must they be able to render assistance to each other; the larger they are, the longer they can be left to depend on themselves. If we only call to mind what has been said in the preceding book on this subject, and also consider that in cultivated countries at a few miles distance from the main road there are always other tolerably good roads running in a parallel direction, it is easy to see that, in regulating a march, there are no great difficulties which make rapidity and precision in the advance incompatible with the proper concentration of force.—In a mountainous country parallel roads are both scarce, and the difficulties of communication between them great; but the defensive powers of a single column are very much greater.
In order to make this idea clearer let us look at it for a moment in a concrete form.
A Division of 8000 men, with its artillery and other carriages, takes up, as we know by experience in ordinary cases, a space of about three miles; if, therefore, two Divisions march one after the other on the same road, the second arrives one hour after the first; but now, as said in the sixth chapter of the fourth book, a Division of this strength is quite capable of maintaining a combat for several hours, even against a superior force, and, therefore, supposing the worst, that is, supposing the first had to commence a fight instantaneously, still the second Division would not arrive too late to support it. Further, within three miles right and left of the road on which we march, in the cultivated countries of central Europe there are, generally, lateral roads which can be used for a march, so that there is no necessity to go across country, as was so often done in the Seven Years’ War.
Again, it is known by experience that the head of a column composed of four Divisions and a reserve of cavalry, even on indifferent roads, generally gets over a march of fifteen miles in eight hours; now, if we reckon for each Division three miles in depth, and the same for the reserve cavalry and artillery, then the whole march will last thirteen hours. This is no great length of time, and yet in this case forty thousand men would have marched over the same road. But with such a mass as this we can make use of lateral roads, which are to be found at a greater distance, and therefore easily shorten the march. If the mass of troops marching on the same road is still greater than above supposed, then it is a case in which the arrival of the whole on the same day is no longer indispensable, for such masses never give battle now the moment they meet, usually not until the next day.
We have introduced these concrete cases, not as exhausting considerations of this kind, but to make ourselves more intelligible, and by means of this glance at the results of experience to show that in the present mode of conducting War the organisation of marches no longer offers such great difficulties; that the most rapid marches, executed with the greatest precision, no longer require either that peculiar skill or that exact knowledge of the country which was needed for Frederick’s rapid and exact marches in the Seven Years’ War. Through the existing organisation of Armies, they go on now almost of themselves, at least without any great preparatory plans. In times past, battles were conducted by mere word of command, but marches required a regular plan, now the order of battle requires the latter, and for a march the word of command almost suffices.
As is well known, all marches are either perpendicular [to the front] or parallel. The latter, also called flank marches, alter the geometrical position of the Divisions; those parts which, in position, were in line, will follow one another, and vice versâ. Now, although the line of march may be at any angle with the front, still the order of the march must decidedly be of one or other of these classes.
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 (1757).
* 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 battlefield 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, except 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 kept up constantly 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* 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.
[* ]Leuthen, 5th Dec. 1757.
[* ]Fifth Chap. ?—Tr.