On War

by Carl von Clausewitz

By this covering it is not at all meant that a portion of the army is to be detached to defend the space round its wings, in order to prevent the enemy from approaching these weak points, as they are called: who would then defend the wings of these flanking corps? This kind of idea, which is so common, is complete nonsense. The wings of an army are in themselves not weak points of an army for this reason, that the enemy also has wings, and cannot menace ours without placing his own in jeopardy. It is only if circumstances are unequal, if the enemy’s army is larger than ours, if his lines of communication are more secure (see Lines of Communication), it is only then that the wings become weak parts; but of these special cases we are not now speaking, therefore, neither of a case in which a flanking corps is appointed in connection with other combinations to defend effectually the space on our wings, for that no longer belongs to the category of general dispositions.

But although the wings are not particularly weak parts still they are particularly important, because here, on account of flanking movements the defence is not so simple as in front, measures are more complicated and require more time and preparation. For this reason it is necessary in the majority of cases to protect the wings specially against unforeseen enterprises on the part of the enemy, and this is done by placing stronger masses on the wings than would be required for mere purposes of observation. To press heavily these masses, even if they oppose no very serious resistance, more time is required, and the stronger they are the more the enemy must develop his forces and his intentions, and by that means the object of the measure is attained; what is to be done further depends on the particular plans of the moment. We may therefore regard corps placed on the wings as lateral advanced guards, intended to retard the advance of the enemy through the space beyond our wings and give us time to make dispositions to counteract his movement.

If these corps are to fall back on the main body and the latter is not to make a backward movement at the same time, then it follows of itself that they must not be in the same line with the front of the main body, but thrown out somewhat forwards, because when a retreat is to be made, even without being preceded by a serious engagement, they should not retreat directly on the side of the position.

From these reasons of a subjective nature, as they relate to the inner organisation of an army, there arises a natural system of disposition, composed of four or five parts according as the reserve remains with the main body or not.

As the subsistence and shelter of the troops partly decide the choice of a position in general, so also they contribute to a disposition in separate divisions. The attention which they demand comes into consideration along with the other considerations above mentioned; and we seek to satisfy the one without prejudice to the other. In most cases, by the division of an army into five separate corps, the difficulties of subsistence and quartering will be overcome, and no great alteration will afterwards be required on their account.

We have still to cast a glance at the distances at which these separated corps may be allowed to be placed, if we are to retain in view the advantage of mutual support, and, therefore, of concentrating for battle. On this subject we remind our readers of what is said in the chapters on the duration and decision of the combat, according to which no absolute distance, but only the most general, as it were, average rules can be given, because absolute and relative strength of arms and country have a great influence.

The distance of the advanced guard is the easiest to fix, as in retreating it falls back on the main body of the army, and, therefore, may be at all events at a distance of a long day’s march without incurring the risk of being obliged to fight an independent battle. But it should not be sent further in advance than the security of the army requires, because the further it has to fall back the more it suffers.

Respecting corps on the flanks, as we have already said, the combat of an ordinary division of 8000 to 10,000 men usually lasts for several hours, even for half a day before it is decided; on that account, therefore, there need be no hesitation in placing such a division at a distance of some leagues or one or two miles, and for the same reason, corps of three or four divisions may be detached a day’s march or a distance of three or four miles.

From this natural and general disposition of the main body, in four or five divisions at particular distances, a certain method has arisen of dividing an army in a mechanical manner whenever there are no strong special reasons against this ordinary method.

But although we assume that each of these distinct parts of an army shall be competent to undertake an independent combat, and it may be obliged to engage in one, it does not therefore by any means follow that the real object of fractioning an army is that the parts should fight separately; the necessity for this distribution of the army is mostly only a condition of existence imposed by time. If the enemy approaches our position to try the fate of a general action, the strategic period is over, everything concentrates itself into the one moment of the battle, and therewith terminates and vanishes the object of the distribution of the army. As soon as the battle commences, considerations about quarters and subsistence are suspended; the observation of the enemy before our front and on our flanks has fulfilled the purpose of checking his advance by a partial resistance, and now all resolves itself into the one great unit—the great battle. The best criterion of skill in the disposition of an army lies in the proof that the distribution has been considered merely as a condition, as a necessary evil, but that united action in battle has been considered the object of the disposition.