Lectures on Land Warfare; A tactical Manual for the Use of Infantry Officers / An Examination of the Principles Which Underlie the Art of Warfare, with Illustrations of the Principles by Examples Taken from Military History, from the Battle of Thermopylae, B.C. 480, to the Battle of the Sambre, November 1-11, 1918

by Anonymous

(g) Among the examples of Advanced Guard work in Marshal Foch's "Principles of War" is a problem for a battalion as the Advanced Guard of a Brigade. "What is the problem the battalion commander has to solve? It consists in preparing for the brigade to go into action against an enemy who may debouch from Bettwiller. What does the brigade require for such an action? It requires the space necessary for the full employment of its forces, and the time necessary for their arrival and deployment. In order to achieve that double task the battalion commander orders his troops to occupy the whole space necessary, and places them in points where they may hold on for the necessary time."

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FLANK ATTACKS AND FLANK GUARDS

"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.