Translation of a Memorandum, dated 11th July, 1915,
drawn up by General CASTELNAU, Commanding the Group of Armies
of the Centre.
The Commander-in-Chief in a recent memorandum laid down general principles to be applied and the steps to be taken to deal with the type of attack as practiced at present by the enemy.
These attacks are invariably preceded by a heavy and prolonged bombardment.
Experiments carried out both by ourselves and by the Germans lead one to the conclusion that it is merely a question of employing the necessary amount of heavy artillery in order to ensure the destruction of hostile trenches. Defensive organisations are demolished. Judiciously placed shell-proof casemates and subterranean dug-outs, of which the Germans have rightly made such extensive use, are alone capable of resistance.
Hence it is no longer a question of spreading men all along a line which was considered proof to any attack; it is necessary to keep a large proportion of them in hand so that they can be brought up wherever they may be required.
For an army acting on the defensive the battle has only begun, when the enemy has crossed the front trenches. It lies with the Commander to have in hand the necessary resources in infantry and artillery, to enable him to intervene at the right moment.
Therefore, Army Commanders should take the necessary steps:-
1. To diminish the numbers in occupation of the front line trenches. The onus of defence should fall on small groups, judiciously distributed, supported by machine guns. The number of observation posts, shell-proof flanking casemates and subterranean dug-outs should be increased.
2. To organise sector reserves along the whole front.
3. To keep in reserve complete formations which can be easily moved.
4. To be able to reinforce rapidly the artillery on the front attacked. This implies the preparation of numerous emplacements, the allotment of zones of fire in advance, (destruction of enemy trenches and counter-batteries, tir de barrages.)
But it is not sufficient to pre-arrange the composition of sector and army reserves; it is essential that they should be able to come into action when and where they are wanted.
As a violent and continued bombardment, which is intended to destroy the front lines, generally begins one or more days before the attack proper, the local commander can anticipate this and make his preparations accordingly.
If the front line trenches are demolished, their garrison will be transferred to swell the numbers in the support trenches or redoubts and “points d’appui” situated to the rear. (Defensive organisations in depth are essential).
It is here, that it will be possible to check the enemy’s attack and to counter-attack so as to drive the enemy back. The success of a counter-attack depends on surprise and determination.
If delivered by the sector reserves, it must take place immediately. This is feasible:
1. If the details of execution have been minutely prepared in advance.
2. If these reserves are thoroughly familiar with the sector.
3. If their moral is unshaken (this entails their being kept immune from bombardment).
4. If they are well provided with grenades.
5. If our own artillery has kept up a continuous fire on the trenches which have been lost in order to prevent the enemy from establishing himself there, and has opened a tir de barrage to prevent the arrival of supports.
The counter-attack, carried out by Army reserves, should be as rapid as possible. For this purpose it is necessary to have studied and prepared their mode of action and employment in good time.
The enemy should not be allowed time to reorganize on the ground they have occupied, otherwise the whole thing will have to be started afresh like an ordinary attack against an organized front, which requires working out and preparing in every detail.
In order to use reserves in this way, it will be necessary:-
1. To have been able to withdraw them, if possible, from the effects of the bombardment and of the asphyxiating gasses (numerous alarm posts and shelters).
2. To be able to use them in spite of the enemy’s tir de barrage, (a study being made beforehand of their mode of employment; numerous communication trenches, a proportion of which will be strictly reserved for evacuation of wounded, dividing the ground into sectors etc.)
3. To have foreseen and prepared the action of the batteries specially entrusted with supporting the counter-attack (reinforcing batteries, preparation of emplacements, allotment of zones of fire etc.)
Whether carried out by Sector or Army reserves, the counter-attack must always be driven home. Exploit to the full the confusion and disorganization likely to arise in the enemy’s ranks, in order not only to drive him back to his own line but also to gain as firm a footing as possible in the hostile trenches.
An Army should deal with an attack delivered by a few brigades with its own reserves, without having to draw upon the reserves of the group of armies. The employment of the latter is worthy of consideration for such tasks as penetrating still further into the enemy’s position in the track of the Army reserves, and breaking the front, if opportunity offers.
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