From the subject of the foregoing chapter, the general endeavour to attain a relative superiority, there follows another endeavour which must consequently be just as general in its nature:  this is the surprise of the enemy.  It lies more or less at the foundation of all undertakings, for without it the preponderance at the decisive point is not properly conceivable.

The surprise is, therefore, not only the means to the attainment of numerical superiority; but it is also to be regarded as a substantive principle in itself, on account of its moral effect.  When it is successful in a high degree, confusion and broken courage in the enemy’s ranks are the consequences; and of the degree to which these multiply a success, there are examples enough, great and small.  We are not now speaking of the particular surprise which belongs to the attack, but of the endeavour by measures generally, and especially by the distribution of forces, to surprise the enemy, which can be imagined just as well in the defensive, and which in the tactical defence particularly is a chief point.

We say, surprise lies at the foundation of all undertakings without exception, only in very different degrees according to the nature of the undertaking and other circumstances.

This difference, indeed, originates in the properties or peculiarities of the Army and its Commander, in those even of the Government.

Secrecy and rapidity are the two factors in this product and these suppose in the Government and the Commander-in-Chief great energy, and on the part of the Army a high sense of military duty.  With effeminacy and loose principles it is in vain to calculate upon a surprise.  But so general, indeed so indispensable, as is this endeavour, and true as it is that it is never wholly unproductive of effect, still it is not the less true that it seldom succeeds to a remarkable degree, and this follows from the nature of the idea itself.  We should form an erroneous conception if we believed that by this means chiefly there is much to be attained in War.  In idea it promises a great deal; in the execution it generally sticks fast by the friction of the whole machine.

In tactics the surprise is much more at home, for the very natural reason that all times and spaces are on a smaller scale.  It will, therefore, in Strategy be the more feasible in proportion as the measures lie nearer to the province of tactics, and more difficult the higher up they lie towards the province of policy.

The preparations for a War usually occupy several months; the assembly of an Army at its principal positions requires generally the formation of depots and magazines, and long marches, the object of which can be guessed soon enough.

It therefore rarely happens that one State surprises another by a War, or by the direction which it gives the mass of its forces.  In the seventeenth and eighteenth centuries, when War turned very much upon sieges, it was a frequent aim, and quite a peculiar and important chapter in the Art of War, to invest a strong place unexpectedly, but even that only rarely succeeded.(*)