Tuesday, 13 October 2020

Tuesday’s Serial: “On War” by General Carl von Clausewitz (Translated into English by Colonel J.J. Graham) – XXI

 CHAPTER VII - Advanced Guard and Out-Posts

These two bodies belong to that class of subjects into which both the tactical and strategic threads run simultaneously. On the one hand we must reckon them amongst those provisions which give form to the battle and ensure the execution of tactical plans; on the other hand, they frequently lead to independent combats, and on account of their position, more or less distant from the main body, they are to be regarded as links in the strategic chain, and it is this very feature which obliges us to supplement the preceding chapter by devoting a few moments to their consideration.

Every body of troops, when not completely in readiness for battle, requires an advanced guard to learn the approach of the enemy, and to gain further particulars respecting his force before he comes in sight, for the range of vision, as a rule, does not go much beyond the range of firearms. But what sort of man would he be who could not see farther than his arms can reach! The foreposts are the eyes of the army, as we have already said. The want of them, however, is not always equally great; it has its degrees. The strength of armies and the extent of ground they cover, time, place, contingencies, the method of making war, even chance, are all points which have an influence in the matter; and, therefore, we cannot wonder that military history, instead of furnishing any definite and simple outlines of the method of using advanced guards and outposts, only presents the subject in a kind of chaos of examples of the most diversified nature.

Sometimes we see the security of an army intrusted to a corps regularly appointed to the duty of advanced guard; at another time a long line of separate outposts; sometimes both these arrangements co-exist, sometimes neither one nor the other; at one time there is only one advanced guard in common for the whole of the advancing columns; at another time, each column has its own advanced guard. We shall endeavour to get a clear idea of what the subject really is, and then see whether we can arrive at some principles capable of application.

If the troops are on the march, a detachment of more or less strength forms its van or advanced guard, and in case of the movement of the army being reversed, this same detachment will form the rearguard. If the troops are in cantonments or camp, an extended line of weak posts, forms the vanguard, the outposts. It is essentially in the nature of things, that, when the army is halted, a greater extent of space can and must be watched than when the army is in motion, and therefore in the one case the conception of a chain of posts, in the other that of a concentrated corps arises of itself.

The actual strength of an advanced guard, as well as of outposts, ranges from a considerable corps, composed of an organisation of all three arms, to a regiment of hussars, and from a strongly entrenched defensive line, occupied by portions of troops from each arm of the service, to mere outlying pickets, and their supports detached from the camp. The services assigned to such vanguards range also from those of mere observation to an offer of opposition or resistance to the enemy, and this opposition may not only be to give the main body of the army the time which it requires to prepare for battle, but also to make the enemy develop his plans, and intentions, which consequently makes the observation far more important.

According as more or less time is required to be gained, according as the opposition to be offered is calculated upon and intended to meet the special measures of the enemy, so accordingly must the strength of the advanced guard and outposts be proportioned.

Frederick the Great, a general above all others ever ready for battle, and who almost directed his army in battle by word of command, never required strong outposts. We see him therefore constantly encamping close under the eyes of the enemy, without any great apparatus of outposts, relying for his security, at one place on a hussar regiment, at another on a light battalion, or perhaps on the pickets, and supports furnished from the camp. On the march, a few thousand horse, generally furnished by the cavalry on the flanks of the first line, formed his advanced guard, and at the end of the march rejoined the main body. He very seldom had any corps permanently employed as advanced guard.

When it is the intention of a small army, by using the whole weight of its mass with great vigour and activity, to make the enemy feel the effect of its superior discipline and the greater resolution of its commander, then almost every thing must be done sous la barbe de l’ennemi, in the same way as Frederick the Great did when opposed to Daun. A system of holding back from the enemy, and a very formal, and extensive system of outposts would neutralise all the advantages of the above kind of superiority. The circumstance that an error of another kind, and the carrying out Frederick’s system too far, may lead to a battle of Hochkirch, is no argument against this method of acting; we should rather say, that as there was only one battle of Hochkirch in all the Silesian war, we ought to recognise in this system a proof of the King’s consummate ability.

Napoleon, however, who commanded an army not deficient in discipline and firmness, and who did not want for resolution himself, never moved without a strong advanced guard. There are two reasons for this.

The first is to be found in the alteration in tactics. A whole army is no longer led into battle as one body by mere word of command, to settle the affair like a great duel by more or less skill and bravery; the combatants on each side now range their forces more to suit the peculiarities of the ground and circumstances, so that the order of battle, and consequently the battle itself, is a whole made up of many parts, from which there follows, that the simple determination to fight becomes a regularly formed plan, and the word of command a more or less long preparatory arrangement. For this time and data are required.

The second cause lies in the great size of modern armies. Frederick brought thirty or forty thousand men into battle; Napoleon from one to two hundred thousand.

We have selected these examples because every one will admit, that two such generals would never have adopted any systematic mode of proceeding without some good reason. Upon the whole, there has been a general improvement in the use of advanced guards and outposts in modern wars; not that every one acted as Frederick, even in the Silesian wars, for at that time the Austrians had a system of strong outposts, and frequently sent forward a corps as advanced guard, for which they had sufficient reason from the situation in which they were placed. Just in the same way we find differences enough in the mode of carrying on war in more modern times. Even the French Marshals Macdonald in Silesia, Oudinot and Ney in the Mark (Brandenburg), advanced with armies of sixty or seventy thousand men, without our reading of their having had any advanced guard.—We have hitherto been discussing advanced guards and outposts in relation to their numerical strength; but there is another difference which we must settle. It is that, when an army advances or retires on a certain breadth of ground, it may have a van and rear guard in common for all the columns which are marching side by side, or each column may have one for itself. In order to form a clear idea on this subject, we must look at it in this way.

The fundamental conception of an advanced guard, when a corps is so specially designated, is that its mission is the security of the main body or centre of the army. If this main body is marching upon several contiguous roads so close together that they can also easily serve for the advanced guard, and therefore be covered by it, then the flank columns naturally require no special covering.

But those corps which are moving at great distances, in reality as detached corps, must provide their own van-guards. The same applies also to any of those corps which belong to the central mass, and owing to the direction that the roads may happen to take, are too far from the centre column. Therefore there will be as many advanced guards, as there are columns virtually separated from each other; if each of these advanced guards is much weaker than one general one would be, then they fall more into the class of other tactical dispositions, and there is no advanced guard in the strategic tableau. But if the main body or centre has a much larger corps for its advanced guard, then that corps will appear as the advanced guard of the whole, and will be so in many respects.

But what can be the reason for giving the centre a van-guard so much stronger than the wings? The following three reasons.

 

1. Because the mass of troops composing the centre is usually much more considerable.

2. Because plainly the central point of a strip of country along which the front of an army is extended must always be the most important point, as all the combinations of the campaign relate mostly to it, and therefore the field of battle is also usually nearer to it than to the wings.

3. Because, although a corps thrown forward in front of the centre does not directly protect the wings as a real vanguard, it still contributes greatly to their security indirectly. For instance, the enemy cannot in ordinary cases pass by such a corps within a certain distance in order to effect any enterprise of importance against one of the wings, because he has to fear an attack in flank and rear. Even if this check which a corps thrown forward in the centre imposes on the enemy is not sufficient to constitute complete security for the wings, it is at all events sufficient to relieve the flanks from all apprehension in a great many cases.

 

The van-guard of the centre, if much stronger than that of a wing, that is to say, if it consists of a special corps as advanced guard, has then not merely the mission of a van-guard intended to protect the troops in its rear from sudden surprise; it also operates in more general strategic relations as an army corps thrown forward in advance.

The following are the purposes for which such a corps may be used, and therefore those which determine its duties in practice.

 

1. To insure a stouter resistance, and make the enemy advance with more caution; consequently to do the duties of a van-guard on a greater scale, whenever our arrangements are such as to require time before they can be carried into effect.

2. If the central mass of the army is very large, to be able to keep this unwieldy body at some distance from the enemy, while we still remain close to him with a more moveable body of troops.

3. That we may have a corps of observation close to the enemy, if there are any other reasons which require us to keep the principal mass of the army at a considerable distance.

The idea that weaker look-out posts, mere partisan corps, might answer just as well for this observation is set aside at once if we reflect how easily a weak corps might be dispersed, and how very limited also are its means of observation as compared with those of a considerable corps.

4. In the pursuit of the enemy. A single corps as advanced guard, with the greater part of the cavalry attached to it, can move quicker, arriving later at its bivouac, and moving earlier in the morning than the whole mass.

5. Lastly, on a retreat, as rearguard, to be used in defending the principal natural obstacles of ground. In this respect also the centre is exceedingly important. At first sight it certainly appears as if such a rearguard would be constantly in danger of having its flanks turned. But we must remember that, even if the enemy succeeds in overlapping the flanks to some extent, he has still to march the whole way from there to the centre before he can seriously threaten the central mass, which gives time to the rearguard of the centre to prolong its resistance, and remain in rear somewhat longer. On the other hand, the situation becomes at once critical if the centre falls back quicker than the wings; there is immediately an appearance as if the line had been broken through, and even the very idea or appearance of that is to be dreaded. At no time is there a greater necessity for concentration and holding together, and at no time is this more sensibly felt by every one than on a retreat. The intention always is, that the wings in case of extremity should close upon the centre; and if, on account of subsistence and roads, the retreat has to be made on a considerable width (of country), still the movement generally ends by a concentration on the centre. If we add to these considerations also this one, that the enemy usually advances with his principal force in the centre and with the greatest energy against the centre, we must perceive that the rear guard of the centre is of special importance.

Accordingly, therefore, a special corps should always be thrown forward as an advanced guard in every case where one of the above relations occurs. These relations almost fall to the ground if the centre is not stronger than the wings, as, for example, Macdonald when he advanced against Blücher, in Silesia, in 1813, and the latter, when he made his movement towards the Elbe. Both of them had three corps, which usually moved in three columns by different roads, the heads of the columns in line. On this account no mention is made of their having had advanced guards.

But this disposition in three columns of equal strength is one which is by no means to be recommended, partly on that account, and also because the division of a whole army into three parts makes it very unmanageable, as stated in the fifth chapter of the third book.

When the whole is formed into a centre with two wings separate from it, which we have represented in the preceding chapter as the most natural formation as long as there is no particular object for any other, the corps forming the advanced guard, according to the simplest notion of the case, will have its place in front of the centre, and therefore before the line which forms the front of the wings; but as the first object of corps thrown out on the flanks is to perform the same office for the sides as the advanced guard for the front, it will very often happen that these corps will be in line with the advanced guard, or even still further thrown forward, according to circumstances.

With respect to the strength of an advanced guard we have little to say, as now very properly it is the general custom to detail for that duty one or more component parts of the army of the first class, reinforced by part of the cavalry: so that it consists of a corps, if the army is formed in corps; of a division, if the organisation is in divisions.

It is easy to perceive that in this respect also the great number of higher members or divisions is an advantage.

How far the advanced guard should be pushed to the front must entirely depend on circumstances; there are cases in which it may be more than a day’s march in advance, and others in which it should be immediately before the front of the army. If we find that in most cases between one and three miles is the distance chosen, that shows certainly that circumstances have usually pointed out this distance as the best; but we cannot make of it a rule by which we are to be always guided.

In the foregoing observations we have lost sight altogether of outposts, and therefore we must now return to them again.

In saying, at the commencement, that the relations between outposts and stationary troops is similar to that between advanced guards and troops in motion, our object was to refer the conceptions back to their origin, and keep them distinct in future; but it is clear that if we confine ourselves strictly to the words we should get little more than a pedantic distinction.

If an army on the march halts at night to resume the march next morning, the advanced guard must naturally do the same, and always organise the outpost duty, required both for its own security and that of the main body, without on that account being changed from an advanced guard into a line of outposts. To satisfy the notion of that transformation, the advanced guard would have to be completely broken up into a chain of small posts, having either only a very small force, or none at all in a form approaching to a mass. In other words, the idea of a line of outposts must predominate over that of a concentrated corps.

The shorter the time of rest of the army, the less complete does the covering of the army require to be, for the enemy has hardly time to learn from day to day what is covered and what is not. The longer the halt is to be the more complete must be the observation and covering of all points of approach. As a rule, therefore, when the halt is long, the vanguard becomes always more and more extended into a line of posts. Whether the change becomes complete, or whether the idea of a concentrated corps shall continue uppermost, depends chiefly on two circumstances. The first is the proximity of the contending armies, the second is the nature of the country.

If the armies are very close in comparison to the width of their front, then it will often be impossible to post a vanguard between them, and the armies are obliged to place their dependence on a chain of outposts.

A concentrated corps, as it covers the approaches to the army less directly, generally requires more time and space to act efficiently; and therefore, if the army covers a great extent of front, as in cantonments, and a corps standing in mass is to cover all the avenues of approach, it is necessary that we should be at a considerable distance from the enemy; on this account winter quarters, for instance, are generally covered by a cordon of posts.

The second circumstance is the nature of the country; where, for example, any formidable obstacle of ground affords the means of forming a strong line of posts with but few troops, we should not neglect to take advantage of it.

Lastly, in winter quarters, the rigour of the season may also be a reason for breaking up the advanced guard into a line of posts, because it is easier to find shelter for it in that way.

The use of a reinforced line of outposts was brought to great perfection by the Anglo-Dutch army, during the campaign of 1794 and 1795, in the Netherlands, when the line of defence was formed by brigades composed of all arms, in single posts, and supported by a reserve. Scharnhorst, who was with that army, introduced this system into the Prussian army on the Passarge in 1807. Elsewhere in modern times, it has been little adopted, chiefly because the wars have been too rich in movement. But even when there has been occasion for its use it has been neglected, as for instance, by Murat, at Tarutino. A wider extension of his defensive line would have spared him the loss of thirty pieces of artillery in a combat of out-posts.

It cannot be disputed that in certain circumstances, great advantages may be derived from this system. We propose to return to the subject on another occasion.

 

CHAPTER VIII - Mode of Action of Advanced Corps

We have just seen how the security of the army is expected, from the effect which an advanced guard and flank corps produce on an advancing enemy. Such corps are always to be considered as very weak whenever we imagine them in conflict with the main body of the enemy, and therefore a peculiar mode of using them is required, that they may fulfil the purpose for which they are intended, without incurring the risk of the serious loss which is to be feared from this disproportion in strength.

The object of a corps of this description, is to observe the enemy, and to delay his progress.

For the first of these purposes a smaller body would never be sufficient, partly because it would be more easily driven back, partly because its means of observation that is its eyes could not reach as far.

But the observation must be carried to a high point; the enemy must be made to develop his whole strength before such a corps, and thereby reveal to a certain extent, not only his force, but also his plans.

For this its mere presence would be sufficient, and it would only be necessary to wait and see the measures by which the enemy seeks to drive it back, and then commence its retreat at once.

But further, it must also delay the advance of the enemy, and that implies actual resistance.

Now how can we conceive this waiting until the last moment, as well as this resistance, without such a corps being in constant danger of serious loss? Chiefly in this way, that the enemy himself is preceded by an advanced guard, and therefore does not advance at once with all the outflanking and overpowering weight of his whole force. Now, if this advance guard is also from the commencement superior to our advanced corps, as we may naturally suppose it is intended it should be, and if the enemy’s main body is also nearer to his advanced guard than we are to ours, and if that main body, being already on the march, will soon be on the spot to support the attack of his advanced guard with all his strength, still this first act, in which our advanced corps has to contend with the enemy’s advanced guard, that is with a force not much exceeding its own, ensures at once a certain gain of time, and thus allows of our watching the adversary’s movements for some time without endangering our own retreat.

But even a certain amount of resistance which such a corps can offer in a suitable position is not attended with such disadvantage as we might anticipate in other cases through the disproportion in the strength of the forces engaged. The chief danger in a contest with a superior enemy consists always in the possibility of being turned and placed in a critical situation by the enemy enveloping our position; but in the case to which our attention is now directed, a risk of this description is very much less, owing to the advancing enemy never knowing exactly how near there may be support from the main body of his opponent’s army itself, which may place his advanced column between two fires. The consequence is, that the enemy in advancing keeps the heads of his single columns as nearly as possible in line, and only begins very cautiously to attempt to turn one or other wing after he has sufficiently reconnoitred our position. While the enemy is thus feeling about and moving guardedly, the corps we have thrown forward has time to fall back before it is in any serious danger.

As for the length of the resistance which such a corps should offer against the attack in front, or against the commencement of any turning movement, that depends chiefly on the nature of the ground and the proximity of the enemy’s supports. If this resistance is continued beyond its natural measure, either from want of judgment or from a sacrifice being necessary in order to give the main body the time it requires, the consequence must always be a very considerable loss.

It is only in rare instances, and more especially when some local obstacle is favourable, that the resistance actually made in such a combat can be of importance, and the duration of the little battle of such a corps would in itself be hardly sufficient to gain the time required; that time is really gained in a threefold manner, which lies in the nature of the thing, viz.:

 

1. By the more cautious, and consequently slower advance of the enemy.

2. By the duration of the actual resistance offered.

3. By the retreat itself.

 

This retreat must be made as slowly as is consistent with safety. If the country affords good positions they should be made use of, as that obliges the enemy to organise fresh attacks and plans for turning movements, and by that means more time is gained. Perhaps in a new position a real combat even may again be fought.

We see that the opposition to the enemy’s progress by actual fighting and the retreat are completely combined with one another, and that the shortness of the duration of the fights must be made up for by their frequent repetition.

This is the kind of resistance which an advanced corps should offer. The degree of effect depends chiefly on the strength of the corps, and the configuration of the country; next on the length of the road which the corps has to march over, and the support which it receives.

A small body, even when the forces on both sides are equal can never make as long a stand as a considerable corps; for the larger the masses the more time they require to complete their action, of whatever kind it may be. In a mountainous country the mere marching is of itself slower, the resistance in the different positions longer, and attended with less danger, and at every step favourable positions may be found.

As the distance to which a corps is pushed forward increases so will the length of its retreat, and therefore also the absolute gain of time by its resistance; but as such a corps by its position has less power of resistance in itself, and is less easily reinforced, its retreat must be made more rapidly in proportion than if it stood nearer the main body, and had a shorter distance to traverse.

The support and means of rallying afforded to an advanced corps must naturally have an influence on the duration of the resistance, as all the time that prudence requires for the security of the retreat is so much taken from the resistance, and therefore diminishes its amount.

There is a marked difference in the time gained by the resistance of an advanced corps when the enemy makes his first appearance after midday; in such a case the length of the night is so much additional time gained, as the advance is seldom continued throughout the night. Thus it was that, in 1815, on the short distance from Charleroi to Ligny, not more than two miles,(*) the first Prussian corps under General Ziethen, about 30,000 strong, against Buonaparte at the head of 120,000 men, was enabled to gain twenty-four hours for the Prussian army then engaged in concentrating. The first attack was made on General Ziethen about nine o’clock on the morning of 15th June, and the battle of Ligny did not commence until about two on the afternoon of 16th. General Ziethen suffered, it is true, very considerable loss, amounting to five or six thousand men killed, wounded or prisoners.

If we refer to experience the following are the results, which may serve as a basis in any calculations of this kind.

A division of ten or twelve thousand men, with a proportion of cavalry, a day’s march of three or four miles in advance in an ordinary country, not particularly strong, will be able to detain the enemy (including time occupied in the retreat) about half as long again as he would otherwise require to march over the same ground, but if the division is only a mile in advance, then the enemy ought to be detained about twice or three times as long as he otherwise would be on the march.

Therefore supposing the distance to be a march of four miles, for which usually ten hours are required, then from the moment that the enemy appears in force in front of the advanced corps, we may reckon upon fifteen hours before he is in a condition to attack our main body. On the other hand, if the advanced guard is posted only a mile in advance, then the time which will elapse before our army can be attacked will be more than three or four hours, and may very easily come up to double that, for the enemy still requires just as much time to mature his first measures against our advanced guard, and the resistance offered by that guard in its original position will be greater than it would be in a position further forward.

The consequence is, that in the first of these supposed cases the enemy cannot easily make an attack on our main body on the same day that he presses back the advanced corps, and this exactly coincides with the results of experience. Even in the second case the enemy must succeed in driving our advanced guard from its ground in the first half of the day to have the requisite time for a general action.

As the night comes to our help in the first of these supposed cases, we see how much time may be gained by an advanced guard thrown further forward.

With reference to corps placed on the sides or flanks, the object of which we have before explained, the mode of action is in most cases more or less connected with circumstances which belong to the province of immediate application. The simplest way is to look upon them as advanced guards placed on the sides, which being at the same time thrown out somewhat in advance, retreat in an oblique direction upon the army.

As these corps are not immediately in the front of the army, and cannot be so easily supported as a regular advanced guard, they would, therefore, be exposed to greater danger if it was not that the enemy’s offensive power in most cases is somewhat less at the outer extremities of his line, and in the worst cases such corps have sufficient room to give way without exposing the army so directly to danger as a flying advanced guard would in its rapid retreat.

The most usual and best means of supporting an advanced corps is by a considerable body of cavalry, for which reason, when necessary from the distance at which the corps is advanced, the reserve cavalry is posted between the main body and the advanced corps.

The conclusion to be drawn from the preceding reflections is, that an advanced corps effects more by its presence than by its efforts, less by the combats in which it engages than by the possibility of those in which it might engage: that it should never attempt to stop the enemy’s movements, but only serve like a pendulum to moderate and regulate them, so that they may be made matter of calculation.

 

(*) Here, as well as elsewhere, by the word mile, the German mile is meant.

 

 

CHAPTER IX - Camps

We are now considering the three situations of an army outside of the combat only strategically, that is, so far as they are conditioned by place, time, and the number of the effective force. All those subjects which relate to the internal arrangement of the combat and the transition into the state of combat belong to tactics.

The disposition in camps, under which we mean every disposition of an army except in quarters, whether it be in tents, huts, or bivouac, is strategically completely identical with the combat which is contingent upon such disposition. Tactically, it is not so always, for we can, for many reasons, choose a site for encamping which is not precisely identical with the proposed field of battle. Having already said all that is necessary on the disposition of an army, that is, on the position of the different parts, we have only to make some observations on camps in connection with their history.

In former times, that is, before armies grew once more to considerable dimensions, before wars became of greater duration, and their partial acts brought into connection with a whole or general plan, and up to the time of the war of the French Revolution, armies always used tents. This was their normal state. With the commencement of the mild season of the year they left their quarters, and did not again take them up until winter set in. Winter quarters at that time must to a certain extent be looked upon as a state of no war, for in them the forces were neutralised, the whole clockwork stopped, quarters to refresh an army which preceded the real winter quarters, and other temporary cantonments, for a short time within contracted limits were transitional and exceptional conditions.

This is not the place to enquire how such a periodical voluntary neutralisation of power consisted with, or is now consistent with the object and being of war; we shall come to that subject hereafter. Enough that it was so.

Since the wars of the French Revolution, armies have completely done away with the tents on account of the encumbrance they cause. Partly it is found better for an army of 100,000 men to have, in place of 6,000 tent horses, 5,000 additional cavalry, or a couple of hundred extra guns, partly it has been found that in great and rapid operations a load of tents is a hindrance, and of little use.

But this change is attended with two drawbacks, viz., an increase of casualties in the force, and greater wasting of the country.

However slight the protection afforded by a roof of common tent cloth,—it cannot be denied that on a long continuance it is great relief to the troops. For a single day the difference is small, because a tent is little protection against wind and cold, and does not completely exclude wet; but this small difference, if repeated two or three hundred times in a year, becomes important. A greater loss through sickness is just a natural result.

How the devastation of the country is increased through the want of tents for the troops requires no explanation.

One would suppose that on account of these two reactionary influences the doing away with tents must have diminished again the energy of war in another way, that troops must remain longer in quarters, and from want of the requisites for encampment must forego many positions which would have been possible had tents been forthcoming.

This would indeed have been the case had there not been, in the same epoch of time, an enormous revolution in war generally, which swallowed up in itself all these smaller subordinate influences.

The elementary fire of war has become so overpowering, its energy so extraordinary, that these regular periods of rest also have disappeared, and every power presses forward with persistent force towards the great decision, which will be treated of more fully in the ninth book. Under these circumstances, therefore, any question about effects on an army from the discontinuance of the use of tents in the field is quite thrown into the shade. Troops now occupy huts, or bivouac under the canopy of heaven, without regard to season of the year, weather, or locality, just according as the general plan and object of the campaign require.

Whether war will in the future continue to maintain, under all circumstances and at all times, this energy, is a question we shall consider hereafter; where this energy is wanting, the want of tents is calculated to exercise some influence on the conduct of war; but that this reaction will ever be strong enough to bring back the use of tents is very doubtful, because now that much wider limits have been opened for the elements of war it will never return within its old narrow bounds, except occasionally for a certain time and under certain circumstances, only to break out again with the all-powerful force of its nature. Permanent arrangements for an army must, therefore, be based only upon that nature.

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