Editing First day on the Somme (section)

===Strategic developments===

{{see also|Battle of Verdun}}

In July 1915, the French [[Grand Quartier Général (1914–1919)|Commander in Chief]] [[Joseph Joffre]] held the first [[inter-Allied conference at Chantilly|Allied conference at Chantilly]]. In December, a second conference agreed a strategy of simultaneous attacks by the French, Russian, British and Italian armies. The British theatre of operations was in northern France and Flanders but in February 1916, Haig accepted Joffre's plan for a combined attack astride the Somme river, around 1 July; in April, the [[British Cabinet]] agreed to an offensive in France.{{sfn|Edmonds|1993|pp=3–4, 10, 13, 29}} The nature of a joint offensive on the Somme began to change almost immediately, when the German army attacked Verdun on 21 February. In March, Foch proposed a Somme offensive on a {{cvt|45|km|order=flip}} front, between Lassigny and the Somme with {{nowrap|42 French}} divisions and a British attack on a {{cvt|25|km|order=flip}} front from the Somme to Thiepval with {{nowrap|25 divisions.}} French divisions intended for the joint offensive were soon diverted to Verdun and the offensive was eventually reduced to a main effort by the British and a supporting attack by the French [[Sixth Army (France)|Sixth Army]].{{sfn|Philpott|2009|pp=100, 102}}

====BEF reinforcements====
[[File:Bassin de la Somme.svg|thumb|{{centre|Bassin de la Somme}}]]
The Somme was to be the first mass offensive mounted by the [[British Expeditionary Force (World War I)|British Expeditionary Force]] (BEF) and the first battle to involve a large number of [[New Army (British)|New Army]] divisions, many composed of [[Pals battalion]]s that had formed after Kitchener's call for volunteers in August 1914.{{sfn|Middlebrook|1971|pp=268–270}} By the end of the [[Gallipoli Campaign]], twelve British divisions were in Egypt and from 4 February to 20 June, nine were transferred to France. From Britain and Egypt the [[34th Division (United Kingdom)|34th Division]] and [[35th Division (United Kingdom)|35th Division]] arrived in January, the [[31st Division (United Kingdom)|31st Division]] and the [[46th (North Midland) Division]] in February, the [[29th Division (United Kingdom)|29th Division]], [[39th Division (United Kingdom)|39th Division]], [[1st Australian Division]] and [[2nd Division (Australia)|2nd Australian Division]] in March, the [[New Zealand Division]] in April, the [[41st Division (United Kingdom)|41st Division]], [[61st (2nd South Midland) Division]] and [[63rd (2nd Northumbrian) Division]] in May, the [[40th Division (United Kingdom)|40th Division]], [[60th (2/2nd London) Division|60th (2/2nd London)]], [[4th Division (Australia)|4th Australian]] and [[5th Division (Australia)|5th Australian]] divisions in June and the [[11th (Northern) Division]] on 3 July. The [[55th (West Lancashire) Infantry Division|55th (West Lancashire) Division]] and [[56th (1/1st London) Division]] were reassembled, a battalion of the [[Newfoundland Regiment]] and the [[1st Infantry Brigade (South Africa)|South African Brigade]] joined in April, followed by a contingent of the [[Bermuda Volunteer Rifle Corps]] in July.{{sfn|Edmonds|1993|p=24}}

Despite considerable debate among German staff officers, General [[Erich von Falkenhayn]], the head of {{lang|de|[[Oberste Heeresleitung]]}} (OHL, the supreme command of the German Army) insisted on a tactic of rigid defence of the front line in 1916 and implied after the war that the psychology of German soldiers, shortage of manpower and lack of reserves made the policy inescapable, since the troops necessary to seal off breakthroughs did not exist. High losses incurred in holding ground by a policy of no retreat were preferable to higher losses, voluntary withdrawals and the effect of a belief that soldiers had discretion to avoid battle. When a more flexible policy was substituted later, discretion was still reserved to army commanders.{{sfn|Sheldon|2006|p=223}} Despite the certainty by mid-June of an Anglo-French attack on the Somme against the [[2nd Army (German Empire)|2nd Army]], Falkenhayn sent only four divisions, keeping eight in the western strategic reserve. No divisions were moved from the [[6th Army (German Empire)|6th Army]], despite it holding a shorter line with {{frac|17|1|2}} divisions and three of the divisions in {{lang|de|OHL}} reserve being in the 6th Army area. The maintenance of the strength of the 6th Army at the expense of the 2nd Army on the Somme, indicated that Falkenhayn intended a counter-offensive against the British to be made closer to Arras north of the Somme front, once the British offensive had been shattered.{{sfn|Foley|2007|pp=248–249}}