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Tactics and Duties
for
Trench Fighting

By

Georges Bertrand

Capitaine, Chasseurs Alpins, de l’Armée de France

and

Oscar N. Solbert

Major, Corps of Engineers, U.S.A.

With Diagrams

G. P. PUTNAM’S SONS

NEW YORK AND LONDON

The Knickerbocker Press

1918

Copyright, 1918

BY

OSCAR N. SOLBERT

The Knickerbocker Press, New York

FOREWORD

It must be borne in mind that this book deals with principles and examples of methods of warfare, and not fixed rules. There are no fixed methods in warfare. Development in warfare means change of methods or the invention of new ones to overcome military difficulties. However, one must have knowledge of past and present methods to be ready for the next logical step of development.

Headquarters, Fort Sheridan Training Camp, Ill.,

October 26, 1917.

From: Major O. N. Solbert, C. of E.

To the Adjutant General, U. S. Army, through official channels.

Subject: Publication of Lectures.

I. Request authority to publish in pamphlet form lectures given at this camp on Trench Fighting.

Major, C. of E.

1st Indorsement

Office of the Senior Instructor, Fort Sheridan Training Camp, Illinois, October 26, 1917.

To the Commanding Officer:

Earnestly recommending that the lectures referred to above be published in pamphlet form. I consider it most desirable that every graduate of this camp take these lectures with him, upon being commissioned. I do not believe that the best interests of the service will suffer, in any way by publishing these lectures.

Lt. Colonel, Infantry,
Senior Instructor.

2nd Indorsement

Hq., The Fort Sheridan Training Camp, October 26, 1917.

To the Adjutant General of the Army, Washington, D. C.

I. Approved.

Colonel of Cavalry,
Commanding.

War Department, A. G. O., October 31, 1917.

To Headquarters, The Fort Sheridan Training Camp, Fort Sheridan, Ill.

Returned.

I. Approved.

By order of the Secretary of War:

Adjutant General.

CONTENTS

Tactics and Duties for Trench Fighting

CHAPTER I
ORGANIZATION OF THE COMPANY FOR BATTLE FORMATIONS

I. Specialists

The exigencies of modern warfare, especially of trench warfare, have developed new infantry weapons. As there are several kinds of these weapons to each infantry company, the men detailed to handle them must be trained as specialists. The weapons are:

• Hand grenades
• Rifle grenades
• Automatic-machine rifles
• Rifles

The men who use these weapons are respectively known as:

• Hand grenadiers
• Rifle grenadiers
• A. M. R. crews
• Riflemen

As a consequence of the new weapons, a company is now organized on a basis of these specialists. A typical company is patterned like that of the French, the only difference being in the number of specialists. Each of the four platoons of a company contains the same number of specialists and each platoon is divided into four sections of specialists.

Organization of a Typical Company

One lieutenant (1st and 4th platoons under 1st lieutenants; 2nd and 3rd platoons under 2nd lieutenants).

One sergeant (second in command, assistant to platoon commander).

Platoon—1st Section—Hand and Rifle Grenadiers

1 Sergeant, pistol and rifle. 3 Corporals, pistol and rifle. 6 Privates, 1st class, all with rifles, two of them with pistols. 12 Privates. —— 22 men.

2nd and 3rd Sections—Riflemen

2 Corporals, rifle and pistol. 3 Privates, 1st class, rifle. 7 Privates, rifle. —— 12

4th Section—Automatic Riflemen

1 Sergeant, pistol and rifle. 1 Corporal, pistol and rifle. 3 Privates, 1st class (automatic rifle gunners, including 1 extra). 6 Privates, rifle. —— 11

Officers

1 Captain. 3 First Lieutenants. 2 Second Lieutenants. — 6

The platoon is the self-contained unit with the proper proportion of all the different kinds of specialists for the assault. The reason for this is that the platoon is the largest unit that one leader can control in combat. The four platoons are alike and therefore interchangeable.

Although it is true that the specialists are particularly trained with their own weapons, all men of the company are first trained as riflemen. All specialists carry rifles, and if for any reason they cannot use their special weapon they immediately become riflemen. Also every man is trained in hand grenade throwing. This makes it possible to fill gaps in the specialists’ ranks from the riflemen. Some men also, usually to the number of the A. M. R. crews, must be trained to operate the automatic-machine rifles.

The remaining supernumeraries of the company, such as mess and supply sergeants, mechanics, cooks, buglers, etc., do not march with the company in maneuver or combat formations. Some of the above supernumeraries will be found in the captain’s headquarters, or tactical group, such as the liaison agents from the platoons, orderlies, buglers, and observers. Mess and supply sergeants, cooks, etc., remain with the regimental train in rear, with the kitchen behind the artillery positions. The tactical group of the captain lives in an adjoining dugout to that of their chief in the sector. In the fight these latter are used as messengers or observers.

II. Use of Specialists

The following table shows the evolution of infantry armament since the beginning of the war:

Outside the company is the 37 mm. gun in the battalion and trench mortars and engines, permanent equipment of the trenches.

In the Defensive

Hand Grenades. Hand grenades are used to produce a short-range defensive barrage at a distance of about 30 yards in front of the trenches. For this purpose one grenade thrower is required for from 10 to 16 yards of frontage.

They are also used to establish centers of resistance; to protect important features of the lines, such as salients, machine gun or automatic rifle posts, command posts, listening posts, etc.

They are used to defend a barricade in a communicating trench. In this latter case the grenades may be thrown from a special bombing post established for that purpose or from an adjoining trench.

Rifle Grenades. Rifle grenades are employed to establish a barrage at a greater range than that of the hand grenade, being used up to as great a distance as 300 yards. The great advantage of the rifle grenade barrage is that it is under the control of the platoon leader and can be called into service immediately, which is not always true of the artillery barrage.

Several grenade rifles concentrated on a trench will stop hand grenade throwing from the same. Rifle grenades are usually shot from the cover trench immediately in rear of the fire trench.

Automatic-Machine Rifles. In the defensive the A.M.R’s are usually employed to obtain flanking fire from the firing line, but may be used in the cover trench and sometimes in shallow holes out in front. In interior fighting they are used to cover stretches of communicating trenches against an enemy that has penetrated the first line.

Riflemen. The riflemen are placed in the intervals between the specialists in the firing line. They are also used as snipers and as sentinels. These sentinels are not to be confused with watchers, who may or may not carry rifles.

In the Offensive

Hand Grenades. In the offensive, hand grenades are used to reach the enemy under cover in trenches, etc., by high-angle throwing. It is an excellent weapon to clear out the trenches that the assaulting columns are advancing against. The H. G. and the R. G. break the resistance, so to speak, of the line that the attack is to capture and the assaulting troops are to occupy and hold. The places of the hand grenadiers in the assaulting column are seen in the diagram.

The hand grenade is the principal weapon in trench combat—that is, to obtain progress laterally and in depth in the trenches after a breach has been made at one point, as every foot of trench has to be fought for. Each section of trench, between traverses, is cleared of the enemy by throwing H. G’s into it. It is then occupied and the next section cleared and occupied in a similar manner.

In a raid on the enemy’s trenches hand grenades are used to clear up the particular stretch of trenches before the raiding party jumps into them. This will be taken up in detail later.

Rifle Grenades. The rifle grenade in the offensive is employed similarly to the hand grenade, to reach an enemy under cover, but at a greater distance.

It is used to help reduce all nests of resistance that the assaulting infantry runs up against, and when the artillery barrage is not obtainable for that purpose.

They may be used as a barrage to cut off the retreat of a small group of the enemy that is being attacked in front.

Rifle grenades are very useful against counterattacks, especially before machine guns can be brought up and the defensive artillery barrage obtained.

The A. M. R. The A. M. R., with its great mobility and ease of control, makes it possible to carry this weapon in the assault and to be used immediately the wave is halted for any reason. In this connection, it can be instantly employed against a nest of resistance.

It is used in the assault to protect the flanks of the assaulting waves, especially when stopped.

As the A. M. R’s are brought up in the first wave, they are immediately available against counterattacks upon the captured position. In a similar manner they are employed to hold ground gained until an artillery barrage can be obtained to support it and before the machine guns come up.

The Riflemen. The riflemen, with bayonets fixed, do the necessary fighting in the interior of the enemy’s position. As was stated before, the H. G. and the R. G. break the enemy’s resistance and the rifleman does the hand-to-hand fighting required to occupy the objective lines of trenches.

To make a little résumé, we may say that the best results will be obtained by the proper combination of all of these weapons. The low trajectory weapons (rifle, A. M. R., H. G., and the 37 mm. gun) concentrate on everything that shows itself above the trenches; while the high-angle missiles (H. G. and R. G.) seek out the enemy under cover. The riflemen complete the success of the specialists by rushing forward and occupying the enemy’s position and fighting hand to hand for it if necessary.

III. Formations for Maneuvering this Resultant Company of Specialists

(Formation of the Platoon)

Initial Formation. The initial formation of the platoon in sections of specialists as per diagram is almost self-explanatory. Each group of specialists is in this formation under the control of its leader ready for any maneuver.

The platoon is the attacking unit because it contains all the specialists required for the assault. The frontage of an offensive is composed of a series of platoons, each with a definite objective, and each with reinforcing platoons in depth following.

All other formations, whether for combat or ordinary march maneuvers, are based upon this initial formation.

Close Order and March Formations. From the initial formation, we pass to the close order formations, used for parade, roll call, or the march.

(a) First we have the company in line, which is the habitual formation for assembly.

(b) From the company in line is formed a column of fours, for marching. The squads that are complete execute “squads right or left,” while the remaining odd number of specialists in any section execute the easiest movement to bring them into column of fours, sometimes with blank files behind the rest of their section.

Approach March. The approach march is a name given to the formations that the platoon in section columns takes up to minimize casualties while crossing the zone of artillery fire.

These formations are taken up under the conditions of open warfare, or, in the case of reinforcements, following up an attack.

The formations may be in “Line of Section Columns” or “Double Line of Section Columns.” In the first case, each section may be in single file or in double column; or again the first and fourth platoon section may be in double column and the second and third sections in single file: In the “Double Line of Section Columns” any of the formations in the diagrams may be taken up, depending upon circumstances.

The interval between sections is variable, but usually the interval is such as to give room for the proper development into line of skirmishers.

Skirmishers. This formation of skirmishers is not taken up for the assault, but under similar conditions as that of the approach march—that is, for open warfare and for the advance of the reinforcing platoons behind an attack.

To form the skirmish line, each section column simply deploys into line, each man going either right or left front into line from the regular formation of double line of section column.

If you inspect the figure, you will see that this deployment into skirmish line gives practically the type formation of the first reinforcing platoon in the assaulting column.

Assaulting Formations. In the attack the platoon forms and goes forward in waves. A wave is not one line of men, but is composed usually of two or three lines.

The composition of the lines of the wave depends upon the duties and functions of the different specialists during the attack.

Let us recapitulate the functions of the specialists in order to show the reasons for their positions in the assaulting wave.

The First Line of the Assaulting Wave. In this line are the grenadiers, whose duty it is to clear the enemy out of the objective trenches. Here also are the A. M. R’s, employed to protect the flanks of the wave. When the wave is halted, the A. M. R’s must be available for instant use against any nest of resistance and must therefore be in the first line. They are also used in the captured trench to withstand an enemy’s counterattack, which may develop within five minutes after its capture.

The Second Line of the First Wave. We have here the rifle grenadiers who help the hand grenadiers break up the enemy’s resistance and clear the trenches of the enemy. This is done by fire of rifle grenades from the second line. Here, also, we have all the riflemen of the platoon, whose function it is to follow up the success of the specialists and drive the surviving hostile men out of the trenches with the bayonet.

Third Line of the First Wave. In this line we have the “trench cleaners” or “moppers-up.” These are hand grenadiers furnished by the reinforcing platoon and their function is to clear the enemy out of the trenches, both laterally and in depth of the position. The assaulting column remains above ground and continues across the position to the objective line of trenches, which is usually the limiting objective of the attack. The “trench cleaners” picket all entrances and exits of dugouts to allow none of the enemy to come out after the waves have passed and fire into the backs of the assaulting troops.

These three lines compose the first wave, and we see that the specialists are placed in the lines in the order of their duties.

Company Drill Regulations Adopted at Fort Sheridan, Illinois, R.O.T.C., in Lieu of No Existing Official Regulations

Company Organization

1. For the purposes of drill and maneuver, the regiment will be organized as follows:

(a) One training company, as at present constituted, will form two platoons.

(b) The new organization contemplates four platoons to the company. When, for training purposes, a complete company is necessary or desirable, companies will be combined.

2. For a training company of two platoons, the 2nd in command (sergeant) of the first platoon is the right guide; the 2nd in command of the 2nd platoon is the left guide.

3. The platoons, in line or column, are arranged as at present.

4. The usual arrangement of a company for attack is to place two platoons in the 1st wave and two in the 2nd wave. The two platoons in the 1st wave are known as the assaulting platoons; the two in the 2nd wave, as the reinforcing platoons. The normal distance between the assaulting and reinforcing platoon is about 65 yards. Sometimes three platoons are placed in the 1st wave and one in the 2nd wave.

5. The first wave is followed, at a distance of 15 yards, by the hand grenadiers of the reinforcing platoon, who are sent forward by the commander of the reinforcing platoon to act as trench cleaners or moppers-up for the first wave. Fifty yards behind these is the remainder of the reinforcing platoon. There are no “moppers-up” for the reinforcing platoon.

6. The captain of a company has four liaison agents constantly with him, one being furnished from and for each platoon. They march immediately in rear of the captain.

7. The post of the captain is between the 1st and 2nd waves.

Platoon Organization

1. The composition of a platoon is as follows:

1 Lieutenant (1st and 4th platoons under 1st Lieutenants).

(2nd and 3rd platoons under 2nd Lieutenants).

1 Sergeant (2nd in command, assistant to platoon leader).

First Section—(Grenadiers).

1 Sergeant—Section Sergeant.

2 Corporals and 12 Privates—Hand Grenadiers.

1 Corporal and 6 Privates—Rifle Grenadiers.

Second Section—(Riflemen).

2 Corporals and 10 Privates—Riflemen.

Third Section—(Riflemen).

2 Corporals and 10 Privates—Riflemen.

Fourth Section—(Automatic Rifle).

1 Sergeant—Charge of 1 gun crew.

1 Corporal—Charge of 1 gun crew.

3 Privates, 1st Class—Gunners—1 in charge of each gun and 1 in reserve.

6 Privates—Ammunition Carriers.

2. All platoons are alike in numbers, organization, and armament.

3. When the platoon is in column of squads or in line, the post of the platoon leader is as at present. When in line of section columns he is normally in front of the right center section, although he may be in front of some other section if he sees fit. In attack formation he is in the center of his platoon between his first and second lines.

4. When the platoon is in line, the post of the 2nd in command is in rear of the center of his platoon. In line of section columns he is in front of the 3rd section. In attack formation he is in rear of the fight center of the second line.

Platoon Movements

1.

1. The 1st Section (Grenadier Section) contains 15 rifle grenadiers (including the section sergeant) and 7 hand grenadiers. When in column of squads, the rifle grenadiers march as a squad, in rear of the hand grenadiers. The 1st Section constitutes 3 squads, each having the No. 3 in the rear rank as a blank file. The Section Sergeant marches abreast of the rear rank of the 2nd squad of his section. Line is formed by executing squads right or left.

2. The 2nd Section (Riflemen Section) contains 10 privates and 2 corporals. One corporal has charge of 7 men, the other of 3 men. When in column of squads, the section forms one complete squad and the front rank of another. Corporals are number four. To form line at the command “Squads left (right),” the complete squad executes “Squad left”; of the half squad the Nos. 3 and 4 execute “Twos left”; the Nos. 1 and 2 likewise execute “Twos left,” thus placing themselves in rear of Nos. 3 and 4. To form column from line at the command “Squads right,” the Nos. 3 and 4 of the incomplete squad move forward two paces, execute “Twos right,” and place themselves in rear of Nos. 3 and 4 of the preceding squad; Nos. 1 and 2 move forward two paces, execute “Twos right,” and place themselves in rear of Nos. 1 and 2 of the preceding squad.

3. The personnel, numbers and movements of the 3rd Section are identical with those of the 2nd.

4. The 4th Section (Automatic Rifle Section) contains 1 sergeant, 1 corporal, and 9 privates (total of 11). One complete squad is formed and 2 privates are left over who march in rear of Nos. 1 and 4 of the squad. The corporal is No. 4 of the front rank. No. 3, front and rear rank, are the gunners. The sergeant marches abreast of the rear rank of the squad in the line of file-closers; when line is formed, the two men left over form one additional file on the left (right) of their sections. In forming for attack formation, the No. 4 of the two men left over attaches himself to the front rank gun crew and goes with them; the No. 1, to the rear rank gun crew. The sergeant remains with his gun crew if the guns are separated, or assumes charge of both when together.

5. If the training company contains more men than are necessary to fill the platoons as indicated above, such additional men will be carried as riflemen and attached to the second and third sections of the platoons.

II

1. To form line of section columns from line.

The left file of each section moves straight to the front, followed by the file next on its right, and this in turn by the other files of the section. The section sergeants of the 1st and 4th sections place themselves at the head of their respective sections.

2. To form line of section columns in columns of twos or fours.

“Half-squads (squads) right front into line.”

3. To form line from line of section columns.

“Sections, right front into line.”

4. To form column of squads from line of section columns.

First form line of section columns in column of squads—then “Column of squads—1st (4th) section forward (column right or left).”

5. To form line of section columns from column of squads.

The left file of the leading section moves straight to the front, followed by the remaining files of the squad, then by the left file of the second squad, etc. The 2nd, 3rd, and 4th sections oblique to the right (left) in column of squads to section interval and, when in rear of their place, form column of files. The section may thus be marched in echelon, or line may be formed by halting the leading section, or the sections in rear may be double-timed to the line established by the leading section.

6. To form line of section columns to the flank, command:

“Sections, column left (right).”

“Line of section columns.”

7. Frequently, for convenience in maneuvering, the platoon leader may, when in line of section columns, wish to form only two columns from his four columns. In such event he will command:

“Double sections, 1st and 4th sections forward.”

One rifle section will follow the first section. The other rifle section, the 4th section. The rifle sections in such formation are always in rear of the specialist sections.

8. Intervals between sections or double sections are opened and closed by the command:

“To —— spaces extend (close).”

III

1. Attack formation is taken up from line of section columns only.

2. The attack formation is always in two lines. The two lines constitute a wave.

3. Hand grenadiers and automatic riflemen are always in the first line. The riflemen and rifle grenadiers are always in the second line in the assaulting platoon. Rifle grenadiers may be posted in the center of the second line, or on either flank, as the platoon leader directs. Similarly the automatic riflemen may be in the center, on either flank, or divided between center and flank of the first line, as the platoon leader may direct.

4. The 1st and 2nd lines are separated by a distance of 20 paces.

5. To pass from line of section columns to attack formation, the platoon leader commands:

“Form for attack at (place). Automatic rifles to center (left flank) (right flank) (both flanks) (left and center). Rifle grenadiers to center (left) (right).”

Only the automatic riflemen and grenadiers need be designated. The remaining men accommodate themselves to their movements.

At the above command the 2nd and 3rd sections stand fast until the 1st and 4th sections have cleared their front. They then move to their places led by the corporal at the head of their respective sections.

This movement will be executed at first in quick time; as men become more proficient, in double time and at a run.

IV

1. The arrangement of specialists in the reinforcing platoon differs somewhat from the assaulting platoon. The hand grenadiers of the reinforcing platoon are sent forward in two squads to follow in rear of the 2nd line of the first wave at a distance of about 15 yards. The two squads are abreast of each other, the section sergeant between them.

2. The rifle grenadiers of the reinforcing platoon are then moved up into the 1st line.

3. The riflemen of the reinforcing platoon remain in the 2nd line.

4. The position of the platoon leader of the reinforcing platoon is in front of the center of the 1st line. The position of the 2nd in command is the same as in the assaulting platoon.

CHAPTER II
DEVELOPMENT OF A POSITION FROM AN OPEN WARFARE BATTLE

General Use of Fortifications. The first use of fortifications, whether hasty or permanent, is to give shelter against hostile fire. The more deliberate use of fortifications is to increase the holding or fighting power of troops by the proper employment of the natural defensive features of the ground and by artificial devices.

Successive Phases of the Organization

Change from Battle Lines to Trenches of a Position. During a battle, as we understand it in open warfare, as soon as the fighting lines are halted for any reason, every man immediately begins to dig in for shelter against the enemy’s fire. If the halting of these fighting lines is more or less permanent these “skirmish holes” are connected, and we have the beginning of a rude trench. We must remember that in a battle troops are disposed in depth in a series of lines. All these lines dig for protection in a similar manner, giving the beginning of several lines of trenches. If the troops remain for any time in this position, it is necessary to have routes from the rear to the front to carry up ammunition and supplies to the different lines. These communication routes are also dug in, and we have the beginning of communicating trenches. Soon the men will begin to seek better protection against rain, cold, and overhead fire, and build themselves some kind of shelters. In a similar manner command posts and supply depots are established.

In time there is a complete skeleton of a series of lines of trenches outlining a position. If the mission of the troops is to remain and hold the ground, the necessary plan of organization for the final position will have to be based upon this skeleton. The purpose of this new organization, as we have noted, is to establish the position so that the ground can be held by fewer troops.

Active and Passive Elements of a Position, Especially Support Points. The first fire trench of a position is continuous, but it is not good practice to man the whole of this line, because this would take too many men and defeat the purpose of the fortifications. Secondly, a better defense can be established by garrisoning a series of strong points, or salients, from which can be obtained flanking fire. In the first line these are called support points. The trenches connecting these support points are retained as such, but are not usually manned. This curtain trench, so to speak, is retained for communicating purposes, and to deceive the enemy as to the real points of defense. A few watchers are left in it.

The first line, then, is a series of support points, well defended by men and special weapons, and at such distances apart as to support each other.

Division of Position. The garrison of such a support point in the first line is a company, and the captain is responsible for the holding of this ground. (The platoon, we must remember, is a tactical unit.) In dividing the first line into these active elements the size of each support point depends upon the importance of the ground or of the tactical situation.

Similar natural strong points are also located in the second line. They will be fewer and farther apart in this line than in the first line, which is exposed to hostile attacks. These points in the second line are connected with the support points and together the group is called a center of resistance. The command of such a center of resistance, including one or two support points in the front line, falls to a battalion commander with his unit. For example, the area of a center of resistance under the command of a Bn. C. O. will include, say, two support points in the first line with a company in each, and the strong point in the second line with two companies.

In the third line, also, natural strong points are located and organized for defense. The command of this strong point, including, let us say, two centers of resistance, falls to a colonel with his regiment. Such an area is called a sector, or a sub-sector. If it is a sub-sector two such constitute a sector in command of a brigadier-general.

Different Lines of a Sector. We have now arrived automatically at the fact that each sector is composed of a series of lines in depth, each defended in strong points.

The first line is termed the line of resistance, as the first defense is made against the enemy’s attacks in the support points of this line.

The second, or main line of resistance, is called the support line. In the strong points of the centers of resistance are the reserves and the headquarters of the battalion commanders.

The third line is called the covering line of the artillery, because it defends the batteries distributed behind it. It also contains the reserve troops of the sector, a battalion usually holding each strong point. Here are established the headquarters of the colonel and the different central depots of the sector.

The above three lines constitute one position. There may be several positions in depth at distances of three miles or more apart. Usually there are two positions and sometimes three. It is said that the Germans have as many as six positions in depth in places. The first position only, of course, is permanently occupied.

Principles of the Organization

Advantages of the Continuous Trench. The continuous or curtain trench between support points must not be eliminated for several reasons. The trench will deceive the enemy as to the location of the elements of support points. If this trench were absent the enemy could easily locate these, and subject them to concentrated artillery fire. The position cannot be hidden from airplane observation but the essential elements, such as emplacements, dugouts, etc., must be concealed.

The curtain trench serves for communicating purposes for lateral movements of troops and for liaison between neighboring units.

The absence of the curtain trench would leave breaches in the line where in a general attack units could concentrate and break through. In such a general attack the curtain trench is occupied and defended by the reserves. Barbed wire, of course, protects the entire front.

These trenches also serve, if necessary, as cover for reserves acting as reinforcements to the adjacent support points, as there is only sufficient shelter in a support point for its own permanent garrison.

Lastly they may serve as trenches of departure in the offensive.

Importance of Flanking Fire. It is possible to have the support points at intervals because flanking fire from these will command all ground in front. The importance of flanking fire cannot be overestimated. Everything must be done to obtain it.

Sometimes it is impossible to obtain flanking fire because of lack of salients. If this is true the trace of the first line trench must be rectified to give flanking fire along the line as per diagram.

When neither of these two methods is possible small combat posts with machine guns are located in advance of the line to obtain flanking fire.

The machine gun is the best weapon for flanking fire. Several emplacements are constructed for each machine gun, but during the bombardment it is kept under cover in a dugout. When the attack develops the machine gun is quickly set up in the proper emplacement. If kept in a permanent emplacement the enemy will soon locate it and put it out of business by artillery fire.

If no emplacements are possible or if they are destroyed machine guns are operated on open ground or in shell holes.

Field of Fire. With proper flanking fire a line can be defended with a shorter field of fire than otherwise. A hundred yards of field of fire is sufficient with good flanking fire and accessory defenses, such as barbed wire, etc.

Location of Trenches. Lines of trenches which are the result of a battle are not always located in the most logical positions. They are the results of the exigencies of the battle. However, it is well to know the best locations for the trenches of a position under different conditions in order to place them there when possible.

In flat country, of course, it makes no difference where the trenches are located. On the profile of a hill, however, the question is where to locate the first and where to locate the second line. Let us consider Figure 15. Point A is out of the question as you have no view of the enemy. At B you can observe the enemy’s line and he can observe yours. However, the enemy can shell you at this point and observe the results. At C the same conditions obtain as at B, except there is a dead angle directly in front. At D you cannot observe the enemy nor can the enemy observe your line. From these considerations we see that the proper location for the first line will be at B as you must be able to observe the enemy and all the ground in front. Your second line should be located at D where the enemy cannot observe and bombard your position. At D the line can be made as elaborate as you have time, men, and material, because you are more or less unmolested by the enemy’s fire and observation.

The reverse slope is of the very greatest importance in organizing a position. Movements of troops and supplies can be easily accomplished here under cover. Deep dugouts can be constructed with the least work. But the greatest advantage lies during the bombardment. The enemy is not able to observe the accuracy of his fire on the reverse slope so that the elements in this line are left more or less intact. For this reason the line on the reverse slope becomes the most important line of resistance against the enemy’s attacks. The Germans habitually organize their reverse slopes very strongly.

Division of the Position into Defensive Compartments. We have already spoken of the sector in depth by successive lines. In the same way it is necessary to organize the positions for lateral defense. A support point may be captured by the enemy and from this ground he can launch a flanking attack on the adjacent part of the position. It is necessary that there should be an established defense against such an attack, and for this purpose each sector is divided into compartments, so to speak, with all-around defense.

Boyaux or communicating trenches on the flanks of these compartments are organized as firing lines with barbed wire belts running parallel and with machine guns disposed for flanking fire. We have then each sector cut up into compartments capable of independent resistance in all directions, if the surrounding compartments are captured by the enemy. Such a compartment also has the advantage of serving as a base for a counterattack against an adjoining one that has fallen into the hands of the enemy.

In a sector the responsibility of such lateral defenses falls especially upon the colonel.

Concealment. All of the essential elements of a position, emplacements, dugouts, etc., are more or less without value if they can be seen by the enemy and subjected to heavy artillery fire. Everything that is possible must be constructed without the observation of the enemy.

It is important to hide your works by making them fit in with the color scheme and shape of the surrounding ground. False or dummy trenches, emplacements, shelters, etc., are constructed to cause the enemy to waste his ammunition. The art of camouflage is also extensively employed for this purpose against both ground and aërial observation.

Elements of the Organization

Plan of Organization. We have seen that the first outline of the trenches left as a consequence of the battle must be modified in detail to obtain better protection and organization. The complete plan of reorganization is laid down by the commander of the sector and is called the Plan of Organization.

This plan is drawn up as soon as the position has a permanent garrison. The Plan of Organization must be faithfully followed by all the successive garrisons of the sector. After its adoption, even the commander of the sector himself cannot modify the plan without the consent of the general in charge.

The real value of the position depends upon the amount of continuous work that has been done in carrying out the original plan.

Outline of the First Line. As was seen before, the original trace of the first line was established as a consequence of the needs of the battle. In the organization plan, it is necessary to introduce several modifications in this trace. The commander responsible for this change should place himself in the situation of the enemy and consider an attack upon his own lines. From this consideration he will introduce such modifications as will make this task as difficult as possible.

The responsibility of making this modification in the trace of the first line does not devolve upon the captain in the first line. As a rule if it were left to him few changes would be made because of lack of initiative on his part, or because of fear that if the line were captured he would be blamed for having changed it. This task falls upon the battalion commander who is responsible for the center of resistance, with the consent of the sector commander. The reason for this is that the sector commander is the only one of these officers who knows the subsequent use of this particular sector, whether for defensive or offensive purposes. If for defensive purposes the line may be carried as close to the enemy’s line as possible. If the sector is being organized for an offensive there must be enough distance between to keep his own line out of the zone of artillery dispersion when the target is the enemy’s line.

Cover Trench. In general all fire trenches have a second trench behind, called the doubling or cover trench. The use of the cover trench is not primarily for defensive purposes. It has special uses.

The majority of the troops in the first line are kept in the cover trench in shelters located there. The first line is habitually manned by only a sufficient number of men to assure observation and security. The rest of the garrison remains in the shelters of the cover trench to get as much rest as possible. It is very important that comfortable shelters be located in the doubling trench. If troops are exposed to the elements and bombardment their value decreases very rapidly. If the shelling becomes too severe the men in the first line retire to the shelters of the cover trench until the attack develops.

Another use of the cover trench in the defensive is to keep here a necessary number of troops for reinforcing the first line when necessary and for counterattack against the same if it is taken. This latter use establishes the distance between the two lines, which is from thirty to forty yards, so that hand grenades can be thrown from the cover trench into the first line.

Behind each support point there is usually a lateral communicating ditch called the circulating ditch which should not be confused with the cover trench.

Advance Posts. In front of the firing line certain advance posts are established. There are three kinds of these: listening, observation, and combat posts.

The listening post is not under the control of the commander of the support point but is in the service of the Intelligence Officer. It is furnished with a microphone for the purpose of picking up enemy’s telephone messages in the hostile line.

The observation post belongs to the sector and is used for purposes of observation and security.

The combat post is established to obtain flanking fire along the barbed wire entanglements or it is used as a bombing post when in close proximity to the enemy’s trenches.

Sometimes a series of combat posts are connected and a new trench established in front of the firing line. This is called the observation line. It is best to avoid this practice as there is always the question whether to hold or abandon this line when the enemy’s attack develops. In either case there are grave disadvantages. If it is held you have a weak line. If you abandon it the enemy can use it for shelter.

Advance posts give excellent service if not too numerous. If there are many of them they are a temptation for hostile raids.

Dimensions of Trenches. These can be found in text-books on the subject. The general idea is that they are to be narrow and deep to prevent observation and to present a small target for high-angle fire.

Loopholes. Loopholes are used in the ordinary life of the trenches for observation and sniping purposes; but against the real attack of the enemy the firing is done over the parapet. If it is necessary to meet the enemy in hand to hand combat the men climb up on the parapet.

Traverses. Traverses are used to localize the effect of shell or grenade explosions, and to prevent enfilade fire.

They are sometimes used in long stretches of boyaux or communicating ditches as emplacements for A. M. R. to enfilade the same if the enemy penetrates the position.

Transversal Lines. Transversal lines are usually constructed between the first and the second lines and between the second and the third lines. They are short stretches of trenches parallel to the front for special purposes: such as disposing of machine guns and trench mortars in depth; bombing posts for rifle and hand grenadiers; depots and observation posts.

Command posts are usually located in such small transversal trenches, a little in rear of the lines they are in command of. For instance, the captain in charge of a support point might be located in a transversal just in rear of the cover trench.

Support Trenches. The second or support line is established at such a distance that the first line is covered by its fire if the latter is captured.

Also the second line should be placed so that it will be out of the zone of dispersion if the first line is the artillery target either of your own or of hostile fire. This places the distance between the two lines at from 150 to 400 yards. At this distance also rifle grenade fire can be used in conjunction with an artillery preparation for a counterattack against the first line.

The organization of the second line is the same as that of the first; in other words, the same principles and elements of defense are used: making employment of barbed wire, flanking fire, cover trenches, etc.

The second line is the main line of resistance and must be made as nearly impregnable as possible. For this purpose it must be thoroughly and completely organized.

In the support line are the reserves of the C. of R. and for their proper shelter they should have very deep dugouts, and all the requisites for the comfort and rest of the troops.

Redoubts. Behind the support line is a redoubt containing the command post of the battalion commander. It is the last strong point of the center of resistance and is organized for an all-around defense.

The line of redoubts is the last line of serious resistance. If the enemy penetrates this line a breach has been made in the position at this point.

Boyaux and Communicating Ditches. As we have said before trenches for communicating purposes must be dug both in depth and laterally. We shall call those from front to rear boyaux, and those running laterally communicating ditches.

The number of boyaux is not fixed as that of the different lines. There must be at least one between each support point and its center of resistance.

Usually boyaux are used for movements in both directions. Often certain boyaux are designated for entrance only and others for evacuation. The numbers of the latter are usually less than the former.

In an attack all boyaux are used for movements from rear to front.

All movements to the rear while reinforcements are being brought up must be executed in the open ground, exceptions being made in the case of wounded.

Boyaux are important for the movement of supplies and ammunition, but above all they are essential for reinforcements during battle. The greater part of the troops in a sector is held in reserve in the second and third lines. This disposition is only possible if you have good boyaux to the front lines.

All boyaux and communicating ditches are narrow and deep. Boyaux are wider between the second and third line than they are between the first and second. Evacuation boyaux are usually wider than others. The trace of a boyau must be such as to prevent enfilade fire.

At intervals of about ten yards turnouts large enough for a stretcher are constructed in the side of the boyaux for passage of troops in different directions. Boyaux are named and signs are put up similar to those for streets in a city. The same name of a boyau must be kept from the third lines to the first.

At branches of the main boyaux they are dug a little deeper to avoid mistakes of identification.

As was said before certain boyaux are organized for defense.

It may be said here that supplies carried up at night are usually brought along on top of the ground close to the boyaux. This gives freer movement and the carriers are close to the cover of the trench if needed.

Accessory Defense. Of all the accessory defenses such as barricades, abatis, trous-de-loup, etc., the most important by far is barbed wire, which is almost exclusively used for obstacles.

Barbed wire should be placed from twenty to fifty yards in front of the first line. At this distance shelling of the barbed wire belts will do very little damage to the first line.

The wire entanglements must be under fire of the first line.

The trace of the wire belt is not necessarily parallel to that of the firing line, but should be so placed as to obtain flanking fire along the wire belts. Good entanglements are constructed in double belts, the distance between the two belts being from ten to twenty yards, the farthest belt, of course, being constructed first.

Breaches must be left through the wire entanglements for the passage of patrols, friendly raiding parties, etc. Portable sections of barbed wire are used to close these passages when necessary.

All accessory defenses must be concealed so they cannot be easily observed and destroyed by the enemy.

Command Post. A command post, in the full sense of the word, contains the headquarters of the leader of a division of a sector.

The command post must first of all be a good observation post, after which the other requisites are installed. When the observation post has been constructed the following are built: a room for the headquarters staff to work and to sleep in, a telephone central, dugout for liaison group, and a depot.

The preceding discussion is a development of a position from battle conditions. On the other hand if you are unmolested by the enemy the order of organizing a position would be as follows:

(1) Construct the emplacement to obtain flanking fire.