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II.—: TACTICS OR THE THEORY OF COMBAT - Carl von Clausewitz, On War, vol. 3 
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. 3.
Part of: On War
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TACTICS OR THE THEORY OF COMBAT
War consists of a combination of many distinct battles. Now, although this combination may be either skilful or the reverse, and the result in a great measure depends upon that point, still the battle itself stands before it in point of importance, for nothing but a combination of successful battles gives a good result. Therefore, the thing of the highest importance in War will always be the art of conquering the enemy in battle. On this your Royal Highness cannot bestow too much attention and thought. The following principles I hold to be the most important:
FOR THE DEFENCE
(1) To keep troops on the defensive under cover from fire as long as possible. As we may be attacked, consequently may have to defend ourselves at any moment, except when we are ourselves acting on the offensive; we must therefore always take up a position as much under cover as possible.
(2) Not to bring the whole force into action at once. If this fault is committed, all rational guidance of the combat is at an end; it is only with disposable troops that we can turn the course of a battle.
(3) To trouble ourselves little about the width of our front, as it is a matter of little consequence in itself, and the depth of the position (that is, the number of troops placed one behind the other) is diminished by an extension of the front. Troops which are in rear of the front line are disposable; they can either be used to restore the combat at that point or be brought forward at other adjacent points. This principle follows from the preceding.
(4) As the enemy, whilst he attacks some part of the front, often seeks to outflank and envelop at the same time, therefore the troops placed in rear are available to repel such attempts, and accordingly supply the want of local obstacles on which to rest the flanks. They are better placed for that purpose than if they stood in line and extended the width of the front, for in such case they themselves would be easily turned by the enemy. This point also further establishes the second.
(5) If there are many troops to be posted in the rear, only a part should be placed directly behind the front, the rest are placed in an oblique direction (in echelon) to the rear, beyond either flank.
From this last position, the enemy’s columns approaching to turn our flank can in turn be taken in flank.
(6) It is a first maxim never to remain perfectly passive, but to fall upon the enemy in front and flank, even when he is in the act of making an attack upon us. We adopt the defensive therefore on a certain line only to compel the enemy to develop his forces for the attack of that line, and we then pass over to the offensive with troops which have been kept in reserve. As your Royal Highness once justly remarked, The art of field fortification is not to serve the defender like a wall behind which he can stand in greater security, but to aid him in attacking the enemy with more success,—the same applies to every passive defence: it is always only the means of attacking the enemy with advantage on ground that we have looked out and prepared for ourselves, and where we have drawn up our troops.
(7) This attack, belonging to the defensive, may be made either at the moment the enemy opens his attack on us, or whilst he is on the march to do so. It may also be arranged so that, when the enemy commences his attack, we draw back and thus lure him on to ground of which he is ignorant, in order to fall upon him on all sides. For all dispositions of this kind, the deep formation of an Army, that is, an order in which only two-thirds or the half, or even less, are in front, and the rest posted directly and obliquely in rear, under cover if possible, is very well suited; and, therefore, this order of battle is a point of infinite importance.
(8) Therefore, if we have two Divisions, it is better to place one behind the other than to place them in line; with three Divisions, one at least should be placed in rear; with four, probably two; with five, at least two, in many cases, three, &c. &c.
(9) At the points where we remain passive, we should make use of field fortification, but only in separate enclosed works of bold profile.
(10) In forming a plan of battle, we should have a great object in view, as, for example, the attack of a strong column of the enemy, and a complete victory over it. If we only choose a small object, whilst the enemy pursues a great one, we shall evidently be the losers. We play with thalers against pfennings.
(11) If our plan of defence is aimed at some great object (the destruction of a column of an enemy, &c.), we must follow it up with the utmost energy, expend upon it all our forces. In most cases, the efforts of the assailant will be in some other direction; whilst we fall upon his right wing, he will be seeking to gain an advantage with his left. If we slacken our efforts sooner than the enemy, if we follow up our object with less energy than he does, he will attain his object, he will gain his advantage completely, whilst we shall only half reach ours. Thus the enemy obtains the preponderance, thus the victory becomes his, and we must give up even our half advantage gained. If your Royal Highness reads attentively the account of the Battles of Ratisbonne and Wagram, you will see both the truth and importance of this.
In both these battles the Emperor Napoleon attacked with his right wing, standing on the defensive with the left. The Archduke Charles did the same. But the one did it with full resolution and energy, the other was undecided, and always stopped half-way. The successes gained by that portion of the Archduke’s Army which was victorious were unimportant; those which the Emperor Napoleon gained in the same time at the opposite point were decisive.
(12) If I may be allowed to bring forward once more the two last principles, the combination of them yields a maxim which, in the modern Art of War, may be regarded as the first among all causes of victory, that is: to follow up a great and decisive object with energy and perseverance.
(13) Danger in case of failure is increased thereby, it is true; but prudence increased at the cost of victory is no Art; it is a false prudence which, as already said, is opposed to the very nature of War; for great ends we must venture much. True prudence is, if we risk anything in War, to select and apply carefully the means to our end, and to neglect nothing through indolence or want of consideration. Of this kind was the prudence of the Emperor Napoleon, who never followed great objects timidly and with half measures through over-prudence.
Among the few victorious defensive battles that are noted in history, you will find, noble Sir, that the greatest were fought in the spirit of these principles, for they are principles derived from the study of history.
At Minden, the Duke Ferdinand suddenly appeared on a field of battle on which the enemy did not expect him, and proceeded to the attack; whilst at Tannhausen he defended himself passively behind entrenchments.
At Rossbach, Frederick II. threw himself on the enemy at a point and at a time where his attack was not expected.
At Leignitz, the Austrians found the King in the night in quite a different position from that in which they had seen him the day before; he fell upon a column of the enemy with the whole weight of his Army, and defeated it before the others could take part in the engagement.
At Hohenlinden, Moreau had five Divisions in his front and four behind him, either directly or obliquely to the rear; he turned the enemy, and fell upon the right-flank column before it could carry out its intended attack.
At Ratisbonne, Marshal Davoust defended himself passively, while Napoleon with the right wing attacked the fifth and sixth Austrian Corps, and completely defeated them.
At Wagram the Austrians were, in reality, on the defensive, still as they attacked the Emperor on the second day with the greater part of their force, we may look upon the latter as acting on the defensive. With his right wing he attacked the Austrian left, turned and beat it, not troubling himself meanwhile about his weak left wing (consisting of a single Division), resting on the Danube; but by means of his strong reserves (deep position) he prevented the victory of the Austrian right wing from having any influence on the victory he had gained on the Rossbach. With these reserves he re-took Aderklaa.
All the foregoing principles are not plainly exemplified in each of the battles enumerated, but all are examples of an active defensive.
The mobility of the Prussian Army under Frederick II. was a means to victory for him, upon which we can no longer build, as other Armies are as capable of moving as ours now.* On the other hand, at that time the turning a flank was less generally in vogue, and, therefore, the deep order of battle was less imperative.
FOR THE ATTACK
(1) We try to fall upon a point in the enemy’s position; that is, a part of his Army (a Division, a Corps), with a great preponderance of force, whilst we keep the other parts in unce tainty, that is to say, occupy them. It is only in this way that when our forces are equal or inferior we can fight with the superiority on our side, that is, with a probability of success. If we are very weak, then we can only spare very few troops to occupy the enemy at other points, that we may be as strong as possible at the decisive point. Unquestionably Frederick II. only gained the battle of Leuthen because he had his small Army on one spot and well concentrated, as compared with the enemy.
(2) The principal blow is directed against a wing of the enemy’s force by an attack in front and flank, or by completely going round it and attacking it in rear. It is only if we push the enemy off his line of retreat by the victory that we gain a great success.
(3) Even when in strong force we often choose only one point for the great shock, and give the blow against that point the greater strength; for to surround an Army completely is seldom possible, or supposes an immense preponderance both physically and morally. But the enemy may also be cut off from his line of retreat by an attack directed against a point in one of his flanks, and that is generally sufficient to ensure great results.
(4) Generally the certainty (high probability) of the victory—that is, the certainty of being able to drive the enemy from the field of battle, is the principal point. Upon this, as an object or end, the plan of the battle must be formed, for a victory once gained, even if it is not decisive, is easily made so by energy in pursuit.
(5) We endeavour to make our attack concentrically on that wing of the enemy which is to receive the shock of our main body, that is, in such a form that his troops find themselves engaged on all sides at once. Allowing that the enemy has troops enough to show a front in all directions, still the troops, under such circumstances, become more easily discouraged; they suffer more, are sooner thrown into disorder, &c.; in short, we may expect to make them give way sooner.
(6) This turning of the enemy compels the assailant to develop a greater force in front than the defender.
If the units a, b, c are to fall concentrically (or by converging lines) on the part e of the enemy’s force, they must naturally stand on lines contiguous to each other. But this development of our force in front must never be carried so far that we do not retain strong reserves. That would be the greatest error possible, and would lead to defeat, if the enemy is only in some measure prepared against being out-flanked.
If a, b, c are units intended to attack e, a part of the enemy’s Army, then the units f, g must be kept in reserve. With this deep formation we can incessantly renew our attacks upon the same point, and if our troops are repulsed at the opposite extremity of the enemy’s position, we are not obliged to give up the day at this, because we have a set-off to any success the enemy may have gained. It was thus with the French at Wagram. The left wing, which was opposed to the Austrian right resting on the Danube, was extremely weak and was totally defeated. Even their centre at Aderklaa was not very strong, and was obliged to give way to the Austrians on the first day. But that did not signify, because the Emperor’s right, with which he attacked the Austrian left in front and flank, had such a depth that he brought a heavy column of cavalry and horse artillery to bear upon the Austrians in Aderklaa, and if he did not beat them, was able, at all events, to stop their progress.
(7) As in the defensive, so in the offensive, that part of the enemy’s Army which, in its destruction, will yield decisive advantages should be the object of attack.
(8) As in the defensive, so here, we must not relax our efforts till we have attained our object, or that our means are entirely exhausted. If the defender is also active if he attacks us at other points, we have no chance of the victory except by surpassing him in energy and boldness. If he remains passive, then, in that case, we run no great danger.
(9) Long, continuous lines of troops are to be particularly avoided, they only lead to parallel attacks which are now no longer to the purpose.
Each Division makes its own attack, although in conformity with the plans of higher authority, and consequently so that they accord with each other. But one Division (8000 to 10,000 men) is never now formed in one line, always in three or four; from this it follows that no long, continuous lines can be used any more.
(10) The attacks of Divisions or Corps in concert must not be combined with the intention of their being under one guidance, so that, although at a distance from each other and perhaps even separated by the enemy, they still remain in communication, even aligning themselves on each other, &c. . This is an erroneous method of carrying out a co-operation, which is liable to a thousand accidents, through which nothing great can ever be effected, and by which one is almost certain to be well beaten if we have to deal with an active, vigorous enemy.*
The true way is to give each Corps or Division Commander the general control of his march, to give him the enemy as the point on which his march is to be directed, and the victory over the enemy as the object of his march.
Each Commander of a column has, therefore, the order to attack the enemy where he finds him, and to do so with all his strength. He must not be made answerable for the result, for that leads to indecision; he must be responsible for nothing more than that his Corps joins in the fight with all its energies and makes any sacrifice that may be necessary.
(11) A well-organised independent Corps can resist the attacks of a vastly superior force for a certain length of time (some hours) and is, therefore, not to be destroyed in a moment; therefore, if it has even been engaged too soon with the enemy and is beaten, still its action is not lost on the whole; the enemy must have deployed his forces, and expended a certain portion of them on this Corps, and thus given our other Corps a favourable opportunity for attack.
Of the organisation of a Corps for this purpose, we shall speak hereafter.
We ensure the harmonious action of the whole in concert when each Corps has in this manner a certain independence, and seeks out the enemy and attacks him at any cost.
(12) One of the most important principles for offensive War is the surprise of the enemy. The more the attack partakes of the nature of a surprise, the more successful we may expect to be. The surprise which the defender effects by the concealment of his dispositions, by the covered position in which he places his troops, the offensive can only effect by the unexpected march to the attack.
This is an occurrence which rarely happens in modern Warfare. This is partly owing to better measures for the security of an Army; partly owing to campaigns being now prosecuted with more vigour, so that there are not now those long pauses in the operations which lulled the one party to sleep, and gave the other a favourable opportunity to make a sudden attack.
Under these circumstances, except by a regular night-surprise (as at Hochkirch), which is always possible, the only way now to surprise an enemy is to make a march to the flank or the rear, and then suddenly return upon him; or if we are at a distance, then by forced marches, and by great efforts, to reach the enemy’s position sooner than he expects.
(13) The regular surprise (by night, as at Hochkirch), affords the best chance of doing something when our Army is small; but it is attended with more risks for the assailant, if the defender knows the country better than he does. The less we know of the country and of the enemy’s arrangements the greater these risks are; therefore, such attacks, in many instances, can only be regarded as desperate means.
(14) In such attacks, all the arrangements must be more simple, and we must keep still more concentrated than by day.
PRINCIPLES FOR THE USE OF TROOPS
(1) Since we cannot dispense with the use of fire-arms (if we could, why should we carry them at all?) we must open the combat with them, and the cavalry should not be employed until the enemy has suffered considerably by the action of infantry and artillery. From this follows:
(a) That the cavalry should be posted behind the infantry.
(b) That we must not be induced to bring the cavalry into action too soon. The cavalry should not be launched boldly to the attack until such disorder prevails in the enemy’s ranks that we may hope for success by his hasty retreat.
(2) The fire of artillery produces greater effect than that of infantry. A battery of eight six-pounders does not occupy a third part of the front of a battalion of infantry, is worked by an eighth of the number of men composing a battalion, and does certainly twice, if not three times, as much execution with its fire.* On the other hand, artillery has the disadvantage of not being so easily moved as infantry. This applies in general, even to the lightest description of horse artillery, for it cannot be used like infantry upon any ground. From the commencement, therefore, the artillery must be kept united at the most important points, because it cannot, like infantry, concentrate itself at those points during the progress of the battle. A great battery of twenty or thirty guns is in most cases decisive at the point where it is placed.
(3) From the particulars just specified and others which are evident, the following rules present themselves for the use of the different arms of the service respectively.
(a) The battle is commenced by artillery. The greater proportion of that arm being brought into use from the very first, it is only with large masses of troops that both horse and foot artillery are kept in reserve. Artillery is used in large masses brought together at single points. Twenty or thirty guns defend the principal point in one great battery, or batter the point in the enemy’s line which it is intended to attack.
(b) We next use light infantry—either marksmen, riflemen, or fusiliers—principally in order not to bring too many troops into action at once; we try first to feel what there is in our front (for that can seldom be properly examined), we want to see which direction the fight as likely to take.
If we can maintain an equal fight with the enemy with this line of skirmishers, and that there is no reason for hastening the affair, we should do wrong to hurry forward other forces; we should weary out the enemy with this kind of fight as much as possible.
(c) If the enemy brings so many troops into the combat as to overpower our line of skirmishers, or if we cannot delay any longer, we bring forward a full line of infantry, which deploys itself at 100 or 200* paces from the enemy, and either opens fire or advances to the attack, according to circumstances.
(d) This is the chief purpose for which the infantry is destined: if we are drawn up in such deep formation that we have still a line of infantry in column in reserve, we are tolerably well master of the combat at this point. This second line of infantry should, if possible, be used only in columns, to decide the day.
(e) The cavalry during this time keeps in rear of the troops engaged in action, as near as it can, without suffering much loss, that is beyond the reach of grape and musketry. It must, however, be at hand, that we may be able to profit by any success which takes place in the course of the combat.
(4) In following these rules more or less strictly, we must keep in view the following principle, on which I cannot insist too strongly, viz., not to make a venture with all our forces at once, because we thus throw away all means of directing them; to weary our adversary with as few troops as possible, and keep in hand a considerable mass for the last decisive moment. Once this last reserve is staked, it must be led with the utmost boldness.
(5) An order of battle, that is, a method of drawing up the troops before and during the battle, must be established for the whole campaign. This order of battle is to be observed in all cases when there is not time to make special dispositions. It must, therefore, be based chiefly with a view to the defensive. This order of battle will reduce the form or manner in which the Army fights to a kind of method, which is very necessary as well as salutary, because a great number of the Generals of second order, and other officers at the head of smaller units, have little knowledge of tactics, and no special aptitude at all for War.
By this, a certain methodicism is instituted which takes the place of art, where the latter is wanting. My persuasion is that this exists to the greatest degree in the French Army.
(6) According to what has been said respecting the use of the different arms of the service, this order of battle for a Brigade would be something like the following:
According to the same principles, a similar disposition may be established for a Corps of larger proportions: at the same time it is not essential that the order adopted should be precisely that now laid down, it may differ in some respects, so that it is in conformity with the foregoing principles. Thus, for instance, the usual position of the cavalry, g, h, may be in the line l, m, and then it is only brought forward when it is found to be too far in rear at l, m.
(7) The Army consists of several such independent Corps, which have their Generals and Staff. They are drawn up in line, or one behind another, according as that may be prescribed by the general principles for the combat. One thing we have still to add, which is, that if we are not too weak in cavalry, we should form a special reserve of that arm, which naturally will be placed quite in rear, and is for the following purposes:
(a) To press upon the enemy, if he retreats from the field, and to attack the cavalry which he employs in covering his retreat. If the enemy’s cavalry is beaten at that moment, great results must follow, unless the enemy’s infantry performs prodigies of valour. Small bodies of cavalry will not answer the purpose on such an occasion.
(b) To hasten the pursuit of the enemy if, without being beaten, he makes a retreat; or if, after a lost battle, he continues to retire on the following day. Cavalry marches quicker than infantry, and is more dreaded by troops that are retreating. And next to beating the enemy, the pursuit is the most important thing in War.
(c) If our object is to make a great turning movement (to turn the enemy Strategically), and on account of the détour we must employ an arm which marches quicker, then we may take this reserve cavalry for the purpose.
In order to make this Corps more independent, horse artillery should be attached to it; for there is greater strength in a combination of several arms.
(8) The order of battle for the troops has relation to the battle; it is their disposition for that end.
The order of march is, in its essentials, as follows:
(a) Each complete unit (whether Brigade or Division) has its own advance- and rear-guard, and forms a column of itself; that does not, however, prevent several such units from marching on the same road one after another, and thus, to a certain extent, forming as a whole one great column.
(b) The units march according to their position in the general order of battle; that is to say, according as their appointed place in that order may happen to be in line with, or in rear of, each other, so they march.
(c) In the columns themselves the following order is invariably observed: the light infantry form the advance- and rear-guards, accompanied by a proportion of cavalry; then follows the infantry; then the artillery; last of all, the rest of the cavalry.
This order is kept, whether we move against the enemy—in which case it is the natural order—or parallel with the enemy, in which case, properly, those who in the order of battle are to stand behind one another should march side by side. If we have to form line of battle, there can never be want of time to such a degree that we cannot withdraw the cavalry and the second line by one flank or the other.
PRINCIPLES FOR THE USE OF GROUND
(1) The terrain (the ground or country) gives two advantages in War.
The first is, that obstacles to approach are thus presented which either render it impossible for an enemy to reach certain points, or compel him to march slowly to keep in column, &c.
The second is, that obstacles of ground enable us to conceal the position of our troops.
Both advantages are very important, but the second appears to me the greatest: at all events it is certainly the one which we can most frequently make use of, because, even the most level country, in most cases, still allows of drawing up troops more or less under cover.
Formerly, the first of these advantages was almost the only one known, and very little use was made of the second. Now the mobility of all Armies is such, that the first is of less service, and just on that account we must make use the more frequently of the second. The first of these two advantages is only serviceable in the defensive, the second, in both attack and defence.
(2) The ground, considered as an obstacle to approach, is of use chiefly in the following points: (a) as a support for the flanks, (b) as a means of strengthening the front.
(3) As a fit support for a flank, an obstacle should be quite impassable—such as a large river, a lake, an impassable swamp. These are all impediments which are rarely met with, and therefore perfect supports for the flanks are seldom to be found, and the want of them is felt now more frequently than formerly, because Armies move more, do not remain so long in one position, consequently require a greater number of positions in the theatre of War.
If the obstacle to approach is not an impassable barrier, then it is, properly speaking, no point d’appui for a flank, it is only a point which strengthens the position. Troops must then be placed behind it, and then again it becomes in relation to these an obstacle to approach.
It is certainly always of advantage to strengthen the flanks in this manner, as fewer troops are then required at those points; but we must take precautions against two things: the first is, placing too much reliance on such supports for the flank, and thus neglecting to have strong reserves behind them; the second is, covering both wings with obstacles of this description, for as they do not completely secure either, they do not prevent the possibility of a combat on both flanks; this may easily become a most disadvantageous defensive, for the obstacles will not allow us easily to sally forth with an active defence on one wing, and thus we may be reduced to defend ourselves in the most unfavourable of all forms, with both flanks thrown back, a d, c b.
(4) These considerations lead again to the deep order
of battle. The less we are able to find secure support for the wings, the more troops we must have in rear, with which we may in turn outflank any portion of the enemy’s army which shall seek to act against our flank.
(5) All kinds of ground which cannot be passed by troops marching in line, all villages, all enclosures of parcels of ground by hedges and ditches, marshy meadows, lastly, all hills which can only be mounted with some difficulty, come under the head of hindrances of this kind, that is, of obstacles that cannot be passed except with difficulty, and slowly; and which, therefore, add greatly to the strength of the troops posted behind them in the combat. Woods can only be included in this category when the underwood is very thick and the ground marshy. A common wood of high trees is as easy to pass as a plain. There is one point, however, in respect to a wood which must not be overlooked, that is, that it may serve to conceal the enemy. If we place ourselves inside it, then there is the same disadvantage for both sides; but it is very dangerous, and at the same time a great mistake to have woods in front or on the flank.* Such a thing can never be allowable unless there are very few roads by which they can be traversed. Abattis intended to bar the passages are so easily removed that they are not of much use.
(6) From all this it follows that we should endeavour to make use of such obstacles upon one flank, in order to offer there a relatively strong resistance with few troops, whilst we carry out our intended offensive on the other flank. With these obstacles, the use of entrenchments may be combined with great advantage, because then, if the enemy passes the obstacle, the fire from the entrenchments may secure our weak force from being overwhelmed by superior numbers, and thrown back too suddenly.
(7) When we are on the defensive, every obstacle covering our front is of great value.
All hills on which positions are taken up are only occupied on this account; for an elevated position has seldom any important influence, often none at all, on the effect of the arms in use. If we stand above the enemy as he approaches, he must ascend with difficulty, therefore he advances only slowly, his ranks get into disorder, and he reaches us with his physical powers exhausted, advantages for us which, with equal bravery and numbers on each side, ought to be decisive. The great effect morally of a rapid charge at full speed is a point which must not on any account be overlooked. The soldier who is advancing becomes insensible even to danger, the one who is standing still loses his presence of mind. It is therefore always advantageous to place the first lines of infantry and artillery on high ground.
If the slope of the hill is so steep, its declivity so broken and uneven, that we cannot sweep it well with our fire, which is often the case, then, instead of placing our front line on the summit ridge, that part should at most only be occupied by skirmishers, and the full line should be so placed on the reverse slope, that at the moment when the enemy reaches the summit ridge and begins to rally his ranks he is exposed to the greatest fire.*
All other local features which form obstacles to approach, such as small rivers, streams, hollow ways, &c., serve to make breaks in the enemy’s front. He must, after passing them, halt to re-form, and that delays him; therefore he should then be brought within range of our most effectual fire. The most effectual fire is case (400 to 600 yards), if there is plenty of artillery available; the fire of musketry (150 to 200 yards), if there is little artillery at hand.
(8) Through this it becomes a rule to include within the zone of our most effective fire every obstacle to approach with which we wish to strengthen our front. But, at the same time, it is important to observe that our whole defence should never depend entirely on our fire, but a considerable portion of our troops (one-third to one-half) should always be kept ready to attack with the bayonet. Therefore, if we are very weak, we must merely place the line of fire (riflemen and artillery) near enough to cover the obstacle with their fire, and place the rest of the troops in columns 600 or 800 yards further back, and if possible under cover.
(9) Another way of making use of obstacles to approach in front is to let them be a little further in front of our line, so that they shall be within the effective range of cannon-shot (1000 to 2000 yards), and if the enemy’s columns pass them, then to attack him from all sides. (At Minden, the Duke Ferdinand did something like this.) In this manner an obstacle of ground is favourable to the plan of actively defending ourselves; and this active defence, of which we have already spoken elsewhere, then takes place on our front.
(10) In the preceding observations, obstacles of ground and country have been considered chiefly as connected lines in relation to extensive positions, but it is necessary to say something about single points.
Isolated points in general can only be defended either by entrenchments or by a strong natural obstacle of ground. Of the first we do not speak at present. Obstacles of ground which, standing isolated, may have to be defended can only be—
(a) Isolated steep Heights.
In this case, entrenchments are indispensable, because the enemy can always advance against the defender with a front more or less extended, and the defender must then at last be taken in rear, because he will rarely be strong enough to show a front on all sides.
Under this term we include every narrow way forming the only approach by which the enemy can reach a particular point. Bridges, embankments, rocky gulleys with precipitous sides, belong to this class.
In respect to all these cases it is to be observed, that either it is impossible for the assailant to turn the obstacle—as, for instance, a bridge over a great river, in which case the defender may then boldly use all his force in order to bring as much fire as possible to bear on the point of passage—or we are not secure against the obstacle being turned—as in the case of bridges over small streams, and the greater number of mountain defiles; then it is necessary to reserve a considerable part of the force (one-third to one-half) for an attack in close order.
(c) Buildings and Enclosures, Villages, small Towns, &c.
If troops are brave, and carry on a War with enthusiasm, there is no place or condition of things in which a few can so well resist many as in the defence of houses. But if we are not quite certain of the men individually, it is better only to occupy the houses, gardens, &c., with riflemen, and to plant guns at the approaches, and to draw up the greater part of the troops (one-third to one-half) in close column, in the place itself, or behind it under cover, in order to rush upon the enemy with this reserve when he attempts to enter.
(11) These isolated posts serve the great operations partly as outposts, not intended to offer an absolute defence, but mostly only to detain the enemy, partly as points which are of importance in the combinations planned for the whole Army. It is also often necessary to hold a distant point, in order to gain time for the development of active defensive measures which we have in view. If the point is remote, it is naturally on that account isolated.
(12) It is only now necessary to add two remarks concerning isolated points, the first is, that we must hold troops in readiness behind these points for the detachments to rally upon in case of being driven out; the second is, that whoever includes such a defence in the series of his combinations should never reckon too much upon it, let the strength of the natural obstacles of ground be ever so great; that, on the other hand, whoever is entrusted with the defence must determine to carry out the object, let circumstances be ever so adverse to him. For this, a spirit of resolution and self-devotion is required which can only spring from a thirst for glory and from enthusiasm: for this reason, men must be chosen for such duties who are not deficient in these noble qualities of the soul.
(13) All that concerns the use of the ground as a means for covering our position and our march up to occupy it requires no elaborate exposition.
We do not now place ourselves on a hill we wish to defend (as was often done formerly) but behind it: we do not place ourselves before a wood, but in it, or behind it; the latter only when we can overlook the wood or thicket. We keep our troops in columns that they may be the more easily concealed; we take advantage of villages, plantations, all undulations of the ground, in order to conceal our troops behind them; in advancing we choose the most broken intersected country,* &c.
In cultivated countries there are hardly any localities so much overlooked that it is not possible by a skilful use of such obstacles and features as the ground presents to keep a great part of the troops on the defensive from being seen. For the assailant, there is more difficulty in keeping a march secret, because he must follow the main loads.
Of course, when the ground is made use of for purposes of concealment of troops, this must be done with a due regard to the end and the combinations which have been decided upon; therefore, in this we must take care above all things that we do not pull to pieces the order of battle, although some small deviations may be allowable.
(14) If we sum up what has now been said on ground, we deduce from it as respects the defensive, that is, the choice of positions, that the following points are those of most importance:
(a) Support of one or both flanks.
(b) Open view before front and flanks.
(c) Obstacles to the approach in front.
(d) Masked positions for troops.
To this is to be added—
(e) A broken country in rear, because that makes pursuit difficult in case of disaster; but no defiles too near (as at Friedland), for that causes delay and confusion.
(15) It would be pedantic to suppose that all these advantages are to be obtained at every position which it is necessary to take up in War. All positions are not of equal importance; their importance increases in proportion to the probability of our being attacked in them. It is only in the most important that we try to combine, if possible, all these advantages; in others we try to do so more or less.
(16) The considerations which the assailant has to study in respect to ground are principally embraced in two leading points: not to choose an over difficult country for the point of attack; and next, on all occasions to advance through the country so that the enemy can see as little as possible of our movements.
(17) I close these observations on the use of ground with a maxim of the highest importance for the defence, and which is to be regarded as the key-stone of the whole theory of defence, which is: Not to expect everything from the strength of the ground, consequently never to be enticed into a passive defence by a strong country. For if the country is in reality so strong that it is impossible for the assailant to drive us out of our position, he will turn it, which is always possible, and then the strongest country is useless; we are then compelled to fight under quite different circumstances, in quite a different country; and we might as well not have included the other locality in our combinations. But if the ground is not of such strength, if it is possible to attack it, still the advantages of such a position will never outweigh the disadvantages of a passive defence. All obstacles of ground must therefore only be taken advantage of for a partial defensive, in order to offer a relatively great resistance with few troops, and to gain time for the offensive, by which the real victory is to be gained at other points.
[* ]Curiously in 1866 the Prussians marched nearly twice as fast as the Austrians, in 1870 nearly three times faster day for day as the French. This superior mobility in both instances conditioned their success. The French had forgotten the secret of marching. The Prussians had learnt it.—Editor.
[* ]The field telegraph and signalling have of course, modified all this.
[* ]The modern quick-fiiring battery of four guns can deliver easily 8000 bullets a minute, and occupies forty yards of front, a battalion of 800 men in line takes roughly 400 yards, and can deliver about the same number of bullets.
[* ]To bring these ideas up to date, all that is necessary is to multiply the number of guns and distances by ten—in the form of the battle—there is no material change. Modern cavalry can cover ten times the distance at speed as when Clausewitz wrote.—Editor.
[* ]Modern practice has altered this. Nothing serves better to hamper unity of command in attacking troops than small woods, whose exits are under close fire from the defender’s position.—Editor.
[* ]This was the British practice in the Peninsula and at Waterloo, At Ligny the Prussians stood on the enemy’s side of the hill. Wellington, seeing this from Bry, said, “Old Blücher will get most damnably mauled.”—Editor.
[* ]This no longer holds good. At St. Privat the Prussians attacking across the open carried the position, at Gravelotte the ground being intersected they failed completely. Unity of command is more essential than cover from fire.—Editor.