barely achieved after
dreadful risk--of the French plan.

That plan, inherited from the strategy of Napoleon, and designed in
particular to achieve the success of a smaller against a larger
number, may be most accurately defined as _the open strategic square_,
and its leading principle is "the method of detached reserves."

This strategic conception, which I shall now describe, and which (in a
diagram it is put far too simply) underlies the whole of the
complicated movements whereby the French staved off disaster in the
first weeks of the war, is one whose whole object it is to permit the
inferior number to bring up a _locally_ superior weight against a
_generally_ superior enemy in the decisive time and at the decisive
place.

Let us suppose that a general commanding _twelve_ large units--say,
twelve army corps--knows that he is in danger of being attacked by an
enemy commanding no less than _sixteen_ similar units.

Let us call the forces of the first or weaker general "White," and
those of the second or stronger general "Black."

It is manifest that if White were merely to deploy his line and await
the advance of Black thus,

[Illustration: Sketch 21.]

he would be outflanked and beaten; or, in the alternative, Black might
mass men against White's centre and pierce it, for Black is vastly
superior to White in numbers. White, therefore, must adopt some
special disposition in order to avoid immediate defeat.

Of such special dispositions one among many is the French Open
Strategic Square.

This disposition is as follows:--

White arranges his twelve units into four quarters of three each, and
places one quarter at each corner of a square thus:--

[Illustration: Sketch 22.]

We will give them titles, and call them A, B, C, and D.

If, as is most generally the case in a defensive campaign at its
opening, White cannot be certain from which exact direction the main
blow is coming, he may yet know that it is coming from some one
general direction, from one sector of the compass at least, and he
arranges his square to face towards that sector.

For instance, in the above diagram, he may not know whether the blow
is coming from the precise direction 1, or 2, or 3, but he knows that
it is coming somewhere within the sector XY.

Then he will draw up his square so that its various bodies all face
towards the average direction from which the blow may come.

The SIZE of his square--which is of great importance