Infrantry and artillery moved into the l'Epinette and Houplines subsectors and Armentieres by the 19th of May where the German trenches lay for the most part 200 or 300 yards, but in some places only 60 yards across No Mans Land. They were held by troops of the German XIX. Corps, known also as the 2nd Royal Saxon Corps, under General von Laffert. Von Laffert's sector was bisected by the Lys, which here forms the frontier between France and Belgium. It remained a German Corps sector till the line was broken in our Messines offensive, and is an example of the German practice of including all obstaclc like the Lys within a sector of command and rather than, as was the British wont, making a boundary of it. This frontier district had often in previous history been the scene of conflicts, and Armentières itself had more than once experienced the ravages of invading armies.
The first trench system occupied by the New Zealanders in France extended for some 4 miles to the east and south-east of Armentières from Pear Tree Farm, just south of the Armentièrs Lille railway, to the river Lys, in front of its suburb Houplines.
Away from the trenches, the Sanitary Section undertook responsibility for water supply, street cleaning, collection and destruction of all refuse and waste material, the inspection of dairies estaminets and retail shops where foodstuffs where exposed for sale, the disinfection of premises and clothing, and the supervision and evacuation of cases of infectious diseases among the civil population. During June, for example, 1,200 tons of refuse were disposed of, and the equivalent of 100 miles of streets was swept and cleaned. For the sanitary services thus rendered the Maire of the town paid 40 francs a day. But the Division did not merely efface from the streets the traces of occasional bombardment, but looked after the civil wounded and sick.
At Pont de Nieppe, the north-western suburb, on the high road to Bailleul, the Divisional baths were located in buildings that once formed part of a textile factor and had been used for bleaching and dyeing. These the Division rented at 1,000 francs per month, and here 1,500 men were bathed a day. Here too 40,000 garments were washed and mended a week by 200 women employed by the Division for this purpose.
When I. Anzac, consisting of the 1st 2nd and 4th Australian Divisions, set out for the battlefield on the Somme on first week in July, New Zealand Division's front was now extended southwards to include the adjoining Bois Grenier subsector.
The Battle of the Somme commenced on 1st July. With a view to distracting the enemy's attention and retaining his troops in their areas, active minor operations were undertaken along the whole northern front, both previous to and after the outbreak of the storm. In this liveliness the New Zealanders played their full part. Gas and smoke were repeatedly discharged over the German positions with at least occasionally happy results, as on the night 13th/14th August, when it was established that the enemy had manned his parapet in strength and suffered heavy casualties from the gas and the artillery bombardment which accompanied it. The 24th June dates the inception of a marked increase in artillery expenditure, which was maintained thence onwards for 18 days. During this period the expenditure of ammunition by the Divisional batteries rarely fell under 1,500 and frequently exceeded 3,000 shells a day. Not merely the battery positions and observation posts, but also the "tender spots" behind the German line, the large dumps also, as at La Crois au Bois, and the battalion or regimental headquarters as at the Ferme du Chastel and Ferme des Deux Treilles were subjected to systematic bombardment. Billets were treated with sudden short salvoes.
The instructions for activity of all arms were repeated on 9th July. The Corps Commander then laid it down "that it must be clearly understood that greater risk must be incurred and heavier casualties faced than would be profitable under conditions of trench-warfare." He desired that "all ranks should understand that they had an opportunity of materially assisting the action of our armies in the south, and that special efforts were required of them." Wire-cutting, demolition of parapets, bursts of fire on enemy billets, and raids or gas discharges or dummy raids were to take place nightly. This programme was rigidly adhered to.
Of greatest importance was the series of raids now delivered on the enemy trenches in rapid succession. This species of military enterprise had originated out of the lessons taught by renewed and expensive experience, that no permanent lodgement on a small scale in an enemy's fortified system is, even if possible, worth the inevitable cost. Participants in small raids seldom stayed beyond 15 minutes in the German trenches. The objects of the raids were, while maintaining and developing the offensive spirit in one's own forces, primarily to secure identification from the enemy, to kill or capture the garrisons assaulted, destroy or bring back machine guns and mortars, and weaken his morale. Now there was the added object of retaining his troops. In the stagnant trench warfare, unproductive indeed of large movement but offering extensive scope for resourcefulness' and ingenuity, these operations were on both sides conducted with a very high degree of scientific skill and elaborate preparation.
During the first week in August the 18th Division came into the centre sector of the Corps front between the 5th Australian Division on the right and the New Zealanders on the left. The Rifle Brigade was relieved by troops of the new Division, and the New Zealand front was therefore contracted to its original length. In connection with this re-organisation the 4th Artillery Brigade recovered its 8th 10th and 14th batteries from the respective groups. Various British units were now coming up from the Somme fighting, and several valuable lectures were given on the terrain, the tactical methods of the opposing armies, questions of supply, and experience generally in the battle. Towards the end of the week orders were received that the Division would be relieved by the 51st (Highland Territorial) Division, from the Somme, in order to release it for a period of preparatory training for battle. The relief commenced on 13th August, and was completed on the 18th, when the command of the sector passed to the Highlanders, and the Division marched out after a continuous stay of 3 months in the line.
During this period they had sustained 2500 casualties. 25 officers and 350 other ranks had been killed. 70 officers and 2000 men had been wounded, and 30 men were missing. Some of these last were in enemy hands, others had been blown to pieces by explosive or buried irretrievably in trench cataclysms. On the 14th, 2 battalions of the Rifle Brigade, marching back with the newly issued Lewis gun handcarts to the railhead at Steenwerck, were inspected informally by H.M. the King. The infantry entrained there for the concentration area at Blaringhem. They were followed by the batteries who trekked the 27-mile march with their guns via Estaires, Vieux Berquin and La Motte.
On the 20th the entrainment of the Division was commenced at Arques and St. Omer for a training area east of Abbeville where it was to pass under the command of the X. Corps of the Fourth Army. The concentration in this new area was completed by 22nd August. Headquarters was at Hallencourt, the artillery in billets about Longpre, the 3 infantry brigade areas being Yonville, Airaines and Limercourt respectively.