(in local reserve) would be committed along the Albert–Bapaume road and parallel to it to the north. The cavalry, which had assembled west of Albert, was not to move until roads had been cleared for their advance. Haig had formulated a plan in which success of any magnitude could be exploited but Rawlinson had a much more modest intention of small advances onto high ground and pauses to consolidate, to repulse German counter-attacks, which led to an "unhappy compromise". German preparations Many of the German units on the Somme had arrived in 1914 and made great efforts to fortify the defensive line, particularly with barbed-wire entanglements beyond the front trench, with fewer troops. Railways, roads and waterways connected the battlefront to the Ruhr, the source of material for , dug-outs underground, big enough for each, excavated every . In February 1916, following the (Autumn Battle, Second Battle of Champagne) in 1915, a third defensive position another back from the was begun and was nearly complete on the Somme front when the battle began. The German artillery was organised in (barrage sectors); each infantry officer was expected to know the batteries covering his section of the front line and the batteries had to be ready to engage fleeting targets. A telephone system with lines deep back from the front line linked the artillery. The Somme defences had two inherent weaknesses that the rebuilding had not remedied. The front trenches were on a forward slope, lined by white chalk from the subsoil and easily seen by observers on the British side of no man's land. The defences were crowded towards the front trench, with a regiment having two battalions near the front-trench system and the reserve battalion divided between the and the second position, all within of the front line; most troops were within of the front line, in the new deep dugouts. The concentration of troops forward guaranteed that they would face the bulk of an artillery bombardment, directed by ground observers on clearly marked lines. Digging and wiring of a new third position had begun in May; civilians were moved away and stocks of ammunition and hand-grenades were increased in the front-line. By mid-June, General Fritz von Below (commander of the 2nd Army) and Crown Prince Rupprecht (commander of the 6th Army) expected an attack on the 2nd Army, which held the front from north of Gommecourt to Noyon south