On the 27th of May 1915, during the relieve, and taking the advantage of a pitch dark night and protected by a violent bombardment, a group of Germans jumped in our trench placing a machine-gun section in it. The enfilading fire of those guns caused heavy casualties to the 9th line regiment which delivered a counter-attack.
After useless efforts, the only alternative left was to push actively forward the organization of the remaining portion of the trench so as to render it able to resist, notwithstanding the achievement of the previous object, it is to say the strengthening of the Yser salient at kilometer 16.
From time to time, the enemy tried to attack the trench but each time was repulsed by spontaneous counter-strokes. The enormous casualties suffered, either by the bombardments or by the numerous raids, carried out by the enemy, against the trench, made it deserve the name of: “Death Trench”. (Boyau de la Mort.)
In September 1915, the more urgent works of the Death Trench were nearly finished and could easely suffice to the defence of the left bank of the river at kilometer no 16. The attention of the engineers was then driven on to the construction of the “Cavalier”, work which was to complete the above mentioned defence, by securing it against all attempts of the enemy to cross the river.
The characteristic features of the “Cavalier” comes from the working condition it had to be submitted to, it is to say, to combine the defence as to fit or better to match in the most perfect way to the one of the “Death trench” thus forming a center of the highest possible resistance.
The “Cavalier” in itself presents two different and parallel lines, the first one on the level with the ground, to serve the purpose of round way and communication line, the second, above level thus dominating the whole region. The latter trench is the firing one, the overlooking position of which permitting to carry out enfilading and plunging fires upon the two banks of the river Yser as well as in the Death Trench itself, and on the enemy’s organization round kilometer no 16.
The dead angles of that position were under machine-gun fire and later, automatic rifles were placed at the entrance of the Death Trench, and also in the one connecting it with the “Cavalier”.
The building up of the “Cavalier” was long and cost to our sappers and infantrymen many a toilsome days and many a casualties. Seeing those provoking works, the German indeed did not remain inactive, they frequently ruined our works with their artillery and minenwerfers, inflicting to our troops awful losses.
The close of 1915 marked the end of the grounding of the accessory defences. The emplacements for trench mortars, machine-guns pits were rising little by little, the dug-out for the officer in Command of the “Cavalier” sector, was gradually coming to shape, and the shelters were rising from out the soil.
It was then decided to reduce the occupation of the “Death Trench”.