d 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.
Battles of the Somme, 1916
First phase: 1–17 July 1916
First day on the Somme, 1 July
The first day on the Somme began 141 days of the Battle of the Somme and the opening day of the Battle of Albert. The attack was made by five divisions of the French Sixth Army either side of the Somme, eleven British divisions of the Fourth Army north of the Somme to Serre and two divisions of the Third Army opposite Gommecourt, against the German Second Army of General Fritz von Below. The German defence south of the Albert–Bapaume road mostly collapsed and the French had "complete success" on both banks of the Somme, as did the British from the army boundary at Maricourt to the Albert–Bapaume road. On the south bank the German defence was made incapable of resisting another attack and a substantial retreat began; on the north bank the abandonment of Fricourt was ordered. The defenders on the commanding ground north of the road inflicted a huge defeat on the British infantry, who had an unprecedented number of casualties. Several truces were negotiated, to recover wounded from no man's land north of the road. The Fourth Army lost 57,470 casualties, of which 19,240 men were killed, the French Sixth Army had 1,590 casualties and the German 2nd Army had 10,000–12,000 losses.
Battle of Albert, 1–13 July
The Battle of Albert was the first two weeks of Anglo-French offensive operations in the Battle of the Somme. The Allied preparatory artillery bombardment commenced on 24 June and the Anglo-French infantry attacked on 1 July, on the south bank from Foucaucourt to the Somme and from the Somme north to Gommecourt, 2 miles (3.2 km) beyond Serre. The French Sixth Army and the right wing of the British Fourth Army inflicted a considerable defeat on the German Second Army but from the Albert–Bapaume road to Gommecourt, the British attack was a disaster where most of the c. 60,000 British casualties were incurred. Against Joffre's wishes, Haig abandoned the offensive north of the road, to reinforce the success in the south, where the Anglo-