Tactics and duties for trench fighting

by Georges Etienne Bertrand; Oscar N. Solbert

Thus we see that the assault, which in open ground warfare is the final phase of the battle, is, on the contrary, in trench warfare the first move of the fight. In open warfare, the order of the battle is: the preparation, the approach march and infantry combat, and finally, the assault. An offensive in trench fighting consists of, first, the preparation; next, the assault against the first line; and last of all, the interior fighting for the position.

The cause of this reversion of the rôles of the attacking troops in a trench offensive operation lies in the strength and stability of the fortified front. It is impossible to maneuver against a continuous line which extends without a single breach. It is only possible to maneuver behind the first line or within the position after a breach has been made. If a part of the first line gives way before the pressure of the assailants, the leader of the attacking units pushes forward his troops through this breach without consideration of the strategical value of the part of the line broken.

I. Preparation of the Attack

Front of Attack. The tactical unit for an attack is a division. A division that is placed in the front line for this purpose is called an attacking division. To such a division is assigned the task of attacking and capturing a definite length of front of the hostile position. All the necessary means to carry out this mission are in the hands of the division commander.

The tactical unit for an assault, in this division, is the battalion. Each assaulting battalion is placed in front of that part of the hostile line against which it is to operate, which is called its front of attack. The length of this front is variable with the tactical situation. Also, this length in no way indicates to the enemy the strength of the attacking troops because they are disposed for the attack in depth. According to the size of the front of attack, the battalion commander will place two or three companies in the assaulting column, and two or one company as reinforcing support.

Conditions of the Assault. An assaulting battalion must be disposed in a certain manner, which is called the assaulting disposition. In establishing this disposition, we must consider the distance of the assault and the outline of the assaulting lines.

Distance of the Assault. The distance over which the troops make their assault across “No Man’s Land” must not be too great. This is to avoid as much as possible the enemy’s barrage and machine gun fire. For this reason, parallels of departure or jumping-off trenches, if necessary, may be constructed out in front of the first line for the assembling of the assaulting troops. On the other hand, your own first line should not be so near to the enemy’s position as to be in the zone of artillery dispersion when your own batteries are firing at the enemy’s first line. However, one is not always master of this distance, as it is a result of long fighting and occupation of the two positions. The proper concealment of these attack works, such as the parallels of departure, is an essential condition of success.

The Trace of the Lines of Departure. The trace of the lines of departure must be parallel to the first line of the enemy, not to your own, so that the assaulting troops will simply have to start in a perpendicular direction from the lines of departure to reach their objective. In other words, the assault is a simple frontal attack without maneuvers.

Ground Preparation for the Assault. It follows from the statements of the conditions of the assault and also of the tactical and material preparation of the attack, that the terrain from which these troops will start must be specially organized for this purpose. We have discussed the principles and details of the organization of the position for the defense, and it is clear that these must differ materially from those for the attack. An attack, like a defense, is made with the units disposed in depth. To launch an attack, certain of the defensive works that play but a passive rôle in the resistance, such as barbed wire entanglements, must be rearranged, modified, or partially eliminated. Other elements, such as routes, boyaux, and supply depots that facilitate the forward movement of reinforcements, are multiplied.

Details of the Preparation of the Ground for the Attack. All the details of the preparation of the ground for the attack are laid down in an order called the “Plan of Ground Disposition” issued by the general of the attacking division. This order is divided into two parts: the organization of the works, and their execution.