1 May until 7 May and the bombardment began on 3 May. Bad weather reduced visibility and the bombardment was extended to six days and on 8 May, the artillery began a destructive bombardment on the German front defences, which were severely damaged. In the last four hours, all of the Tenth Army artillery bombarded the German wire and the first and reserve trench lines, ready for the infantry attack at German preparations The German defences had been improved in the ridges, hollows and ravines between Arras and Lens, since the war of movement had ended late in 1914. Barbed wire and chevaux-de-frise obstacles had been placed in front of the German defences and tunnels, caves and trenches, cellars and loopholed buildings had been fortified; avenues of approach were surveyed and registered by the German artillery. The 6th Army had retained most of the plateau of the Lorette Spur and all of the Spur of the White Way and Spur Souchez during the local attacks by the French in March and April. On 9 May, the French line ran about west of the Chapel, to the summit of the Arabs' Spur and by the Great Spur and Spur Mathis, down to the valley west of Ablain. Five German trench lines had been dug from the Arabs' Spur, across the plateau to the Arras–Béthune road near Aix-Noulette. The trench lines were fortified with iron roofs, sandbags, concrete and barbed wire. At every , a machine-gun nest had been built into the trench and small, fortified posts supported the defenders, one to the north-east of the Chapel of Notre Dame de Lorette, with dug-outs over deep. Artillery and machine-guns in Ablain commanded the southern slopes of the ridge and those in Souchez the eastern face of the spur. Guns hidden in Angres and Liévin to the north-east of the plateau commanded the approaches from the plain to the north and along the spur. Below the southern side of the Lorette Spur were Ablain, Souchez and a sugar refinery in buildings along a -length of the banks of the St Nazaire stream, which had been fortified. To the south was Mill Malon and east of the sugar refinery lay marshes. South of Ablain rose wooded heights towards Carency, with the village in a hollow, the houses in five groups, one in the centre and the others facing north, west, south and east, protected