Frederick the Great arranged his cavalry in two lines, and within these lines the tactical units were on the same line of front. Detachments destined to turn the enemy's flank were attached in column to the outer flank of the leading line. As far as I know, a mention of échelon can only be found in one place. In a sketch that accompanies one of the Regulations of July 25, 1744, a squadron of the second line is shown thrown forward at half the distance between the lines and écheloned on the first line, with the obvious intention of securing the outer flank of the first line against local turning movements. Out of this one squadron the whole of our échelon system has grown. Here is the only justification for claiming that the échelon of the second line is of Frederician origin.
Nor, as far as I know, in the tactics of the Napoleonic cavalry is there any trace of échelon in the modern sense. We would do well to seek, in this period of experience in great cavalry battles instruction for the conduct of cavalry against cavalry, and not to sacrifice its lessons for imaginary advantages.
According to all appearances, our modern échelon is but the offspring of peace requirements. The troops were required to be mobile and capable of manœuvre, and a division was required to perform the same stereotyped evolutions as a regiment or a brigade. In the division the échelon of brigades met this requirement admirably, favouring as it did the change to line, a manœuvre which, on its part, was well suited to the necessities of drill in a limited area, and was regarded as the pièce de résistance of all cavalry divisional manœuvres. Many a time have I assisted at these tactical orgies!
We must not neglect the warning that, even in manœuvres, as soon as there is any kind of approach to service conditions, such necessity for change of front never—literally never—occurs. Besides this, the échelon formation has shown itself to be quite unpractical where any real tactical deployment is required off the drill-ground. The question, then, of the circumstances for which it is particularly designed does not appear as yet to have been definitely asked or answered. We have been content with general representations that it increased the power of manœuvre, and thus added to our beloved stereotyped formations.
For years I have striven to clear up these views and to establish their true worth. As long ago as 1903, in my book "Cavalry in Future Wars," I wrote as follows: " ... It is obvious that the formations for approach and attack prescribed by the (old) Regulations are as unpromising of success as they well can be. While affording a possibility of quickly presenting the same formation in any direction, a feat of no possible advantage for war, they seriously impede any deployment to the front. If it is required to launch the first line against the enemy's flank because this is its shortest line, one at least of the following brigades will be masked, and will be hampered in its movements. If, again, it is desired to utilise one of the rear brigades for a flank movement or any similar purpose, the first line has to be checked until the others reach the required position, or else they will certainly arrive too late to co-operate. Furthermore, the formations advocated render it more difficult to derive full benefit from the configuration of the ground."
These deductions have remained, up to now, uncontested. In spite of this, however, the new Regulations uphold the point of view of the old as regards échelon formation in every way, and even vest it with increased importance by confiding to the échelon the duties of the real second line, i.e. of the supporting squadrons of the old Regulations. In the regiment, as in the brigade, depth is to consist in échelon formation, and only exceptionally is a real second line to be formed. The échelons are not only to protect the flank of their own units, and turn against any portions of the enemy's line that may break through, but are also to turn the enemy's flanks (170 and 200).[45] In the division, also, during the advance to attack cavalry, échelon formation will, "as a rule," be ordered. The transition formation thus remains with us not only in name, but in fact, only with the difference that brigades provide for their own depth and flank protection, thus, in fact, being again in themselves écheloned (223, 424, 425).[46] Only when a closer knowledge of the enemy is attained may the brigades come into the same alignment from the commencement, and assume the requisite frontage (426).[47]
In close connection with this modified transition formation, the "change to lines" has also been retained in fact, though no longer designated as such. That is to say, the possibility of a change of front "to the complete flank," i.e. at right angles to the direction of march, is still contemplated (220),[48] and to this end a fresh formation of the division will generally be required, as well as a fresh directing brigade, which takes up the new line of march, and to which the remainder conform in the desired manner. It is apparently a matter of indifference whether the brigades are called lines or brigades. It is, and remains, a purely drill evolution of the division in close formation, a complete change of front to a flank, and is therefore something that would certainly not occur in war if any reasonable sort of information were to hand. If it did occur, it would presuppose the entire failure of reconnaissance and the corresponding incapacity of the leader.
My cavalry instinct forbids me to share the tactical principles that these views entail, and I will therefore again endeavour to make clear that conception of the matter which I hold to be correct.
First, as regards the demands of the Regulations that échelon is to replace depth. In my opinion, the conditions of reality have not in this matter been taken into account. To be able to meet a hostile squadron that has broken through the line, the écheloned squadron, if still in column, must wheel into line, or if, as is probable, already in line, must wheel, and then charge behind the front of its own attacking-line. I consider this, of itself, to be impracticable in the excitement of the fight, a manœuvre that can only be carried out on the drill-ground. We have only to consult any one who has had experience of a cavalry attack to learn how difficult it is to perform such evolutions immediately before the charge.