Editing Battle of the Somme (section)

== Subsequent operations ==
=== Ancre, January–March 1917 ===
{{Main|Operations on the Ancre, January–March 1917}}

After the [[Battle of the Ancre]] (13–18 November 1916), British attacks on the Somme front were stopped by the weather and military operations by both sides were mostly restricted to survival in the rain, snow, fog, mud fields, waterlogged trenches and shell-holes. As preparations for the offensive at Arras continued, the British attempted to keep German attention on the Somme front. British operations on the Ancre from {{nowrap|10 January – 22 February 1917}}, forced the Germans back {{convert|5|mi|km|abbr=on}} on a {{convert|4|mi|km|adj=on|abbr=on}} front, ahead of the schedule of the [[Hindenburg Line#Alberich Bewegung|Alberich Bewegung]] ({{lang|de|Alberich}} Manoeuvre/Operation Alberich) and eventually took {{nowrap|5,284 prisoners}}.{{sfn|Boraston|1920|p = 64}} On {{nowrap|22/23 February,}} the Germans fell back another {{convert|3|mi|km|abbr=on}} on a {{convert|15|mi|km|adj=on|abbr=on}} front. The Germans then withdrew from much of the {{lang|de|R. I Stellung}} to the {{lang|de|R. II Stellung}} on 11 March, forestalling a British attack, which was not noticed by the British until dark on 12 March; the main German withdrawal from the Noyon salient to the Hindenburg Line (Operation Alberich) commenced on schedule on 16 March.{{sfn|Falls|1992|p = 115}}

=== Hindenburg Line ===
{{main|Hindenburg Line#Alberich Bewegung|l1=Operation Alberich}}

Von Falkenhayn was sacked and replaced by Hindenburg and Ludendorff at the end of August 1916. At a conference at Cambrai on 5 September, a decision was taken to build a new defensive line well behind the Somme front. The {{lang|de|Siegfriedstellung}} was to be built from Arras to St. Quentin, La Fère and Condé, with another new line between Verdun and Pont-à-Mousson. These lines were intended to limit any Allied breakthrough and to allow the German army to withdraw if attacked; work began on the {{lang|de|Siegfriedstellung}} (Hindenburg Line) at the end of September. Withdrawing to the new line was not an easy decision and the German high command struggled over it during the winter of 1916–1917. Some members wanted to take a shorter step back to a line between Arras and Sailly, while the 1st and 2nd army commanders wanted to stay on the Somme. ''[[Generalleutnant]]'' von Fuchs on 20 January 1917 said that,

{{blockquote|Enemy superiority is so great that we are not in a position either to fix their forces in position or to prevent them from launching an offensive elsewhere. We just do not have the troops.... We cannot prevail in a second battle of the Somme with our men; they cannot achieve that any more. (20 January 1917){{sfn|Sheldon|2009|p = 4}}|Hermann von Kuhl}}
and that half measures were futile, retreating to the {{lang|de|Siegfriedstellung}} was unavoidable. After the loss of a considerable amount of ground around the Ancre valley to the British Fifth Army in February 1917, the German armies on the Somme were ordered on 14 February, to withdraw to reserve lines closer to Bapaume. A further retirement to the Hindenburg Line ({{lang|de|Siegfriedstellung}}) in [[Alberich (World War I German operation)|Operation Alberich]] began on 16 March 1917, despite the new line being unfinished and poorly sited in some places.{{sfn|Sheldon|2009|pp = 4–5}}

Defensive positions held by the German army on the Somme after November 1916 were in poor condition; the garrisons were exhausted and censors of correspondence reported tiredness and low morale in front-line soldiers. The situation left the German command doubtful that the army could withstand a resumption of the battle. The German defence of the Ancre began to collapse under British attacks, which on 28 January 1917 caused Rupprecht to urge that the retirement to the {{lang|de|Siegfriedstellung}} (Hindenburg Line) begin. Ludendorff rejected the proposal the next day, but British attacks on the First Army – particularly the action of Miraumont (also known as the Battle of Boom Ravine, 17–18 February) – caused Rupprecht on the night of 22 February to order a preliminary withdrawal of c. {{convert|4|mi|km|abbr=on}} to the {{lang|de|R. I Stellung}} (R. I Position). On 24 February the Germans withdrew, protected by [[rear guard]]s, over roads in relatively good condition, which were then destroyed. The German withdrawal was helped by a thaw, which turned roads behind the British front into bogs and by disruption, to the railways, which supplied the Somme front. On the night of 12 March, the Germans withdrew from the {{lang|de|R. I Stellung}} between Bapaume and Achiet le Petit and the British reached the {{lang|de|R. II Stellung}} (R. II Position) on 13 March.{{sfn|Falls|1992|pp = 95–107}} The withdrawal took place from {{nowrap|16–20 March,}} with a retirement of about {{convert|40|km|mi|order=flip|abbr=on}}, giving up more French territory than that gained by the Allies from September 1914 until the beginning of the operation.{{sfn|Simkins|Jukes|Hickey|2003|p=119}}