le for corps and army commanders to know the capacity of each division.
Despite considerable debate among German staff officers, Falkenhayn continued the policy of unyielding defence in 1916.[Note 2] On the Somme front Falkenhayn's construction plan of January 1915 had been completed. Barbed wire obstacles had been enlarged from one belt 5–10 yards (4.6–9.1 m) wide to two, 30 yards (27 m) wide and about 15 yards (14 m) apart. Double and triple thickness wire was used and laid 3–5 feet (0.91–1.52 m) high. The front line had been increased from one trench line to three, 150–200 yards (140–180 m) apart, the first trench occupied by sentry groups, the second (Wohngraben) for the bulk of the front-trench garrison and the third trench for local reserves. The trenches were traversed and had sentry-posts in concrete recesses built into the parapet. Dugouts had been deepened from 6–9 feet (1.8–2.7 m) to 20–30 feet (6.1–9.1 m), 50 yards (46 m) apart and large enough for 25 men. An intermediate line of strongpoints (the Stützpunktlinie) about 1,000 yards (910 m) behind the front line was also built. Communication trenches ran back to the reserve line, renamed the second line, which was as well-built and wired as the first line. The second line was beyond the range of Allied field artillery, to force an attacker to stop and move field artillery forward before assaulting the line.
Anglo-French plan of attack
British intentions evolved as the military situation changed after the Chantilly Conference. French losses at Verdun reduced the contribution available for the offensive on the Somme and increased the urgency for the commencement of operations on the Somme. The principal role in the offensive devolved to the British and on 16 June, Haig defined the objectives of the offensive as the relief of pressure on the French at Verdun and the infliction of losses on the Germans. After a five-day artillery bombardment, the British Fourth Army was to capture 27,000 yards (25,000 m) of the German first line, from Montauban to Serre and the Third Army was to mount a diversion at Gommecourt. In a second phase, the Fourth Army was to take the German second position, from Pozières to the Ancre and then the second position south of the Albert–Bapaume road, ready for an attack on the German third position south of the road towards Flers, when the Reserve Army which included three cavalry divisions, would exploit the success to advance east and then north towards Arras. The French Sixth Army, with one corps on the north bank from Maricourt to the Somme and two corps on the south bank southwards to Foucaucourt, would make a subsidiary attack to guard the right flank of the main attack being made by the British.
German defences on the Somme
After the (Herbstschlacht or Autumn Battles) of 1915, a third defence line another 3,000 yards (2,700 m) back from the Stutzpunktlinie was begun in February 1916 and was almost complete on the Somme front when the battle began. German artillery was organised in a series of sperrfeuerstreifen (barrage sectors); each officer was expected to know the batteries covering his section of the front line and the batteries ready to engage fleeting targets. A telephone system was built, with lines buried 6 feet (1.8 m) deep for 5 miles (8.0 km) behind the front line, to connect the front line to the artillery. The Somme defences had two inherent weaknesses which the rebuilding had not remedied. The front trenches were on a forward slope, lined by white chalk from the subsoil and easily seen by ground observers. 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 Stutzpunktlinie and the second line, all within 2,000 yards (1,800 m) and most troops within 1,000 yards (910 m) of the front line, accommodated in the new deep dugouts. The concentration of troops at the front line on a forward slope guaranteed that it would face the bulk of an artillery bombardment, directed by ground observers on clearly marked lines.
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