Still less would it bespeak a clear idea if those positions which cannot be maintained after the enemy has passed by them, and from which, in consequence of that, the defensive seeks to attack the assailant’s flank, were called flank positions merely because his attack is directed against a flank; for this flank attack has hardly anything to do with the position itself, or, at least, is not mainly produced by its properties, as is the case in the action against a strategic flank.
It appears from this that there is nothing new to establish with regard to the properties of a flank position. A few words only on the character of the measure may properly be introduced here; we set aside, however, completely strong positions in the true sense, as we have said enough about them already.
A flank position which is not assailable is an extremely efficacious instrument, but certainly just on that account a dangerous one. If the assailant is checked by it, then we have obtained a great effect by a small expenditure of force; it is the pressure of the finger on the long lever of a sharp bit. But if the effect is too insignificant, if the assailant is not stopped, then the defensive has more or less imperilled his retreat, and must seek to escape either in haste and by a detour—consequently under very unfavourable circumstances, or he is in danger of being compelled to fight without any line of retreat being open to him. Against a bold adversary, having the moral superiority, and seeking a decisive solution, this means is therefore extremely hazardous and entirely out of place, as shown by the example of 1806 above quoted. On the other hand, when used against a cautious opponent in a war of mere observation, it may be reckoned one of the best means which the defensive can adopt. The Duke Ferdinand’s defence of the Weser by his position on the left bank, and the well-known positions of Schmotseifen and Landshut are examples of this; only the latter, it is true, by the catastrophe which befell Fouqué’s corps in 1760, also shows the danger of a false application.