Tactics and duties for trench fighting

by Georges Etienne Bertrand; Oscar N. Solbert

Obstacles which may hinder the advance of the assaulting column: accessory defenses, such as barbed wire entanglements.

Elements of the defense, such as strong points, machine gun emplacements, observatories, depots, shelters, and dugouts.

Each different kind of target calls for a certain number of rounds of a particular caliber. These calculations of the different numbers of rounds are the results of experience and are set down in tables for the information of the sector commander. The time, therefore, necessary for a proper preparation for the attack is a function of the number and strength of targets. The artillery preparation may last from one to twenty days, but it must continue until the elements of the hostile position are sufficiently destroyed to assure a successful attack.

Before an offensive, there is placed at the disposal of the attacking divisions, besides their regular divisional artillery, a special allotment of batteries. The different calibers of guns are used according to the nature of the target. The largest calibers are employed against the strongest elements of the organization: nests of resistance, strong points, and deep dugouts. Light artillery is used to obliterate trenches and boyaux and interior barbed wire entanglements. Trench mortars serve to destroy the elements of the first line and its accessory defenses.

Plan of Artillery Action. The details for the execution of these different artillery fires are laid down in the plan of action of the artillery of the army corps or of the division. This plan is a part of the plan of battle of the division. These details must be carried out punctually and with precision. The sector commanders are not interested directly in the execution of these fires, but they are in their results.

Duties of the Infantry during the Artillery Preparation. In connection with the artillery fire, the infantry in the position must observe the results of the bombardment and the leaders report their opinion upon its control.

Observation. The observation of the counter-battery fire, long-range fire on communication routes, and destructive fire on the interior of the position, falls upon the artillery’s ground observers and the aviation service. But the duty of observing the results of destructive fire on the enemy’s first line is carried out with the help of the infantry observers. Each regiment must observe the front upon which it is to make the attack. Special attention is paid to the destruction of barbed wire entanglements and machine gun emplacements. The interested infantry does not content itself with a passive observation, but must send out at night, or even in daylight, offensive reconnaissance parties. Their mission is to actually go into the enemy’s first line, to ascertain its condition, and to investigate the breaches in the hostile entanglements. The tactics of such a reconnaissance are the same as for a raid. The information gathered is sent to the division headquarters in the daily report of the intelligence officer or in special information reports.

Control. It is both the privilege and the duty of the infantry commanders to state in their daily reports their opinion on the artillery preparation. If they do not express their exact opinion on the progress of the bombardment, they are liable to pay for their carelessness at the time of the assault.

Destruction of the Enemy’s Position. The experiences of three years of trench warfare have given bitter proof that an attack against an insufficiently destroyed position will not only fail but will result in great losses. It is sheer folly to attempt an assault against undestroyed entanglements, or against a line in which the machine gun posts have not been demolished. One does not oppose materiel with men. In trench warfare, the conquest of the ground is made by the artillery; the infantry follow up this conquest to occupy and to hold the ground. The essential condition for the success of an attack depends upon the proper destruction of the elements of a position by the artillery.

Plan of Battle. The plan of battle depends upon, first, the strength of the enemy, obstacles to the attacking troops, lines of defense, nests of resistances, barbed wire, etc.; and secondly, the mission of the attacking unit and the means at its disposal.