"A man thoroughly penetrated with the spirit of Napoleon's warfare
would hardly fail to make his enemy's communications his first
objective."---Col. G. F. R. HENDERSON.
The Flanks are the most vulnerable points of an army, for an attack
upon these points subjects the defenders to enfilade fire, and is
delivered by troops arrayed in attack formation against an enemy that
is not in a position to repel the attack. The consequences of a
successful Flank Attack are so far-reaching that every effort will be
made by a commander to bring about such a consummation in order that he
may sever his adversary's communications, bring him to the end of his
resources, and deprive him of the means of replenishing them.
If, therefore, there is any possibility of a column on the march being
attacked in flank a force must be detached to protect that flank, and
if both flanks are exposed to attack both must be similarly protected.
The flank is the most vulnerable part of a moving column, and an attack
driven home upon that part has every prospect of success, for it will
be delivered by a force that is distributed in depth against a force
that is protracted in width after changing front to meet the attack,
and the absence of depth in the defending force will deprive the
defence of the principal source of strength in resisting attack.
An independent column is liable to attack on either of its flanks,
unless the nature of the country through which it is passing provides
security for one or the other in the form of an impenetrable feature
(such as a wide, {115} trackless marsh), or an impassable barrier (such
as a neutral frontier). The outer columns of a force moving on
parallel routes will have an exposed flank, while their inner flank is
protected by maintaining touch with the neighbouring column.
Flank Guards may be furnished by the Main Body, or by the Advanced
Guard, and this point will be made clear in the orders for the
operations. Their composition, strength, and distribution, and the
interval at which they move on the flank of the Main Body, are similar
to those of an Advanced Guard, while their action under all
circumstances is governed by the same tactical considerations, the
principle underlying every action of a Flank Guard commander being
compliance with the known intentions of the commander of the Main Body,
and the sacrifice of the interests of the Flank Guard to preserve the
interests of the Main Body. The same duties of reconnaissance and
protection have also to be carried out, and communication with the Main
Body has to be maintained. For the purposes of reconnaissance and
communication Aircraft are even more effective than in Advanced Guard
work, while observation patrols supplement and confirm the reports of
aërial observers. The work of protection varies with the nature of the
country through which the Guard and the Main Body are moving at the
particular time. In open country the Flank Guard may be keeping pace
with the Main Body at a regularly maintained interval, and on parallel
lines. In close country, and in hilly or mountainous districts, it may
be necessary to occupy a successive series of tactical positions on the
exposed flank, any of which can be reinforced and held at need to
safeguard the passage of the Main Body. In order that the whole column
may be protected, from the head of the Main Body to the train in rear,
unbroken touch must be maintained both with the Advanced and the Rear
Guard, and incursions between these forces and itself must be prevented
by the Flank Guard.
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In addition to the protection of a column on the march, Flank Guard
work is of the highest importance on the Lines of Communications and in
the protection of Convoys. On the _Lines of Communications_ raids from
the air or land may always be expected in Manoeuvre Warfare, and one
flank is usually more vulnerable than the other. A _Convoy_, when
parked, is liable to attack from any quarter; and when on the march it
may be assailed from any direction, especially when the adversary can
detach mounted troops, or infantry rendered mobile by motor transport,
or raiding bodies carried in Aircraft. Frequently, however, one flank
only of the Lines of Communications is vulnerable owing to the
geographical or tactical situation, and the work of protecting traffic
or Convoys on the Lines of Communications is Flank Guard work, with due
precautions against surprise from all quarters, the Main Guard
remaining with the Convoy and securing its safe arrival at its
destination, rather than seeking an encounter with the enemy. The most
efficient way to protect a Convoy is to piquet the road daily with
troops sent out from posts on the line; but when it is necessary to
send a Convoy by a route which cannot be protected in this way a
special escort must be provided. The commander of an escort will not
engage the enemy if his task can be accomplished without fighting. If
fighting is inevitable the enemy should be engaged as far from the
Convoy as possible, and it will not be halted and parked, except as a
last resort. In the case of mechanical transport the whole of the
escort will be carried in motor vehicles, and except where parallel
roads are in existence, little can be done to secure flank protection
while on the move. A portion of such escort will move with the Convoy
and a portion will be sent ahead to secure any bridges or defiles which
have to be passed, the outlet of any defile being secured before the
Convoy is permitted to enter the defile. In the case of a horsed
Convoy the escort will usually consist of infantry, with a proportion
{117} of mobile troops. Small Advanced and Rear Guards will be
detailed and sufficient men will be posted along the column to ensure
order and easy communication. The remainder of the escort will usually
move on that flank from which attack is most likely.
The far-ranging raid on the Lines of Communications was a notable
feature of the American Civil War. It was freely employed on both
sides and was often harmful to the object of the attack and usually
profitable to the raiders, especially to those of the South, by reason
of the replenishment of stores. General Turner Ashby, the dashing
cavalry leader in the Shenandoah Valley, was a constant source of
terror to the Northern Generals, and his death while protecting the
movements to _Cross Keys_ (June 6, 1862) was a terrible blow to
Stonewall Jackson, who employed his mounted troops with more skill than
any other commander, Confederate or Federal. General R. E. Lee
possessed a great cavalry leader in J. E. B. Stuart, "but cool-headed
as he was, Lee appears to have been fascinated by the idea of throwing
a great body of horsemen across his enemy's communications, spreading
terror among his supply trains, cutting his telegraphs and destroying
his magazines. Yet in hardly a single instance did such expeditions
inflict more than temporary discomfort on the enemy; and the
Confederate Armies were led more than once into false manoeuvres for
want of the information which only the cavalry could supply. Lee at
_Malvern Hill_ and _Gettysburg_, and, on the side of the North, Hooker
at _Chancellorsville_, and Grant at _Spottsylvania_, owed defeat in
great measure to the absence of their mounted troops on raiding
excursions. In the Valley, on the contrary, success was made possible
because Jackson kept his cavalry to its legitimate duty" (Henderson
"Stonewall Jackson"). In the Russo-Japanese War a column of 500
Cossacks, under Colonel Madritov, made a bold raid on the
communications of the Japanese I. Army in the last days of April, 1904.
The raid involved a {118} ride of 240 miles and was carried out in
entire ignorance of the imminent attack upon General Zasulich's force
by the Japanese I. Army at the _Battle of the Yalu_ (May 1, 1904). On
arrival at his objective Colonel Madritov found nothing to attack, as
the base of the Japanese I. Army had been shifted from the Korean
frontier to a shorter sea base at the Yalu mouth. On his return he
found his General in disordered flight, and had his small force been
available at the Battle of the Yalu it could have protected the retreat
to Hamatan and Feng-hwang-cheng. Raids and attacks outside the centre
of operations, however daring, have no permanent value.
In the South African War a disaster to a Convoy at _Sannah's Post_, or
_Koorn Spruit_ (March 31, 1900), was caused by the absence of
precautions in front of a retreating force, the wagons being permitted
to enter a defile (the Spruit crossed the road at right-angles and was
held by the Boers) before the exit had been secured. Earlier in the
same campaign a Convoy of 800 wagons was lost at _Ramdam_ (February 13,
1900). An ambushed force of Boers killed all the transport animals and
the wagons were abandoned. No escort had been provided for the Convoy,
which entered the ambushed area without previous reconnaissance.
Throughout the South African War the activities of De Wet emphasised
the vulnerability of the Lines of Communications.
Where the tactical situation permits, arrangements should be made to
protect the Lines of Communications by offensive action. An engagement
may be invited in a suitable position, the protecting troops holding
the raiders with a Delaying Action while reinforcements are summoned to
converge on the battlefield for the purpose of surrounding and
exterminating the raiders.
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