For instance, the battle of Königgrätz.
I can relate in a few lines the circumstances under which an event of such far-reaching importance had birth.
Feldzeugmeister Benedek had, in his advance to the northward, to secure himself against the IInd Prussian Army marching on the east over the mountains of Silesia. To this end four of his Corps had one after another been pushed forward on his right flank, and had all been beaten within three days. They now joined the main body of the Austrian Army, which had meanwhile reached the vicinity of Dubenetz.
Here, then, on June 30th, almost the whole of the Austrian forces were standing actually inside the line of operations between the two Prussian armies; of which the Ist was already fighting its way to Gitschin, designated from Berlin as the common point of concentration, and the IInd had also advanced close on the Upper Elbe; thus they were both so near that the enemy could not attack the one without the other falling on his rear. The strategic advantage was nullified by the tactical disadvantage.
In these circumstances, and having already lost 40,000 men in previous battles, General Benedek gave up the advance, and during the night of June 30th began his retreat on Königgrätz.
The movement of six Army Corps and four Cavalry Divisions, marching in only four columns, which were necessarily very deep, could not be accomplished in the course of a single day. They halted very closely concentrated between Trotina and Lipa; but when on July 2nd they still remained there, it was owing to the extreme fatigue of the troops, and the difficulty, nay, impossibility, of withdrawing so large a body of men beyond the Elbe, under the eyes of an active enemy and by a limited number of passages. In fact, the Austrian general could no longer manœuvre; he had no alternative but to fight.
It is a noteworthy fact that neither his advance on Dubenetz nor his retreat on Lipa was known to the Prussians. These movements were concealed from the IInd Army by the Elbe, and the cavalry of the Ist was a mass of more than 8000 horse collected in one unwieldy Corps. The four squadrons attached to each Infantry Division were of course not able to undertake reconnoissances, as subsequently was later done in 1870 by a more advantageous plan of formation.
Thus in the Royal head-quarters at Gitschin nothing certain was known. It was supposed that the main body of the hostile army was still advancing, and that it would take up a position with the Elbe in its front and its flanks resting on the fortresses of Josephstadt and Königgrätz. There were, then, these alternatives—either to turn this extremely strong position, or attack it in front.
By the adoption of the first the communications of the Austrian Army with Pardubitz would be so seriously threatened that it might probably be compelled to retreat. But to secure the safety of such a movement our IInd Army must relieve our Ist and cross over to the right bank of the Elbe. And in this case the flank march of the latter close past the enemy's front might easily be interfered with, if passages enough across the river had been prepared by him.
In the second case, success could only be hoped for if an advance of the IInd Army on the right flank of the enemy's position could be combined with the attack in front. For this it must be kept on the left bank.