Alberich ( World War I German operation ) Alberich was the codename of a German military operation in occupied territory in France during World War I . It was a planned withdrawal to new positions on the shorter , more easily defended Hindenburg Line which took place between 9 February and 15 March 1917 and which eliminated a salient between Arras and Saint - Quentin . The British referred to it as the German Retreat to the Hindenburg Line , but the operation was a strategic withdrawal rather than a retreat . Prelude . Soon after taking over from Erich von Falkenhayn as Chief of the General Staff in September 1916 , Paul von Hindenburg and Ludendorff , " First Generalquartiermeister " ordered the building of a new defensive line east of the Somme battlefront from Arras to Laon . Ludendorff was unsure as to whether retreating to the Hindenburg Line was the best thing to do , since he believed withdrawing might diminish the morale of German soldiers and civilians . The possibility of an offensive was considered if enough reserves could be assembled in the new year . A study suggested that seventeen divisions might be made available but that this was far too few for a decisive effect in the west . He was forced to accept the plan by Rupprecht , Crown Prince of Bavaria , commander of Army Group Rupprecht ( 1st , 2nd , 6th and 7th Armies from the Somme front to the North Sea Coast ) over the objections of the First and Second Army commanders . Other options such as a shorter withdrawal were also canvassed . Manpower made the decision inevitable , since even with reinforcements from the Eastern Front the German army in the west numbered only 154 divisions against 190 Allied , many of which were larger . A move back to the Hindenburg Line ( " Siegfried Stellung " ) would shorten the front by and save the manpower of . The order for the withdrawal to begin was issued on 16 March . Rupprecht was appalled by the scale and methods proposed for a scorched earth policy that would accompany the withdrawal . He decided to resign but reversed his position when it was concluded that him leaving his command might suggest a rift had developed between Bavaria and the rest of Germany . Operation . The operation began on February 9 , 1917 throughout the area that the German army planned to abandon . Railways and road were put out of action , trees were felled , water well s were polluted , towns and villages were destroyed and a large number of mines and other booby - trap s were planted . 125 , 000 able - bodied French civilians in the region were transported to work elsewhere in occupied France , while children , mothers and the elderly were left behind with minimal rations . On March 4 , General Louis Franchet d ' Espèrey , commander of the French Northern Army Group , tried to gain permission to launch a strong attack against the Germans as they were in the process of preparing to retreat . Robert Nivelle , commander - in - chief of the French armies , approved only a limited assault to capture the German front position , meaning the only real opportunity to significantly upset the German withdrawal was lost . The main phase of the withdrawal commenced on March 16 and was completed to a great extent by March 20 . The German army had fallen back to the east over a distance of around 40 kilometers , giving up more French territory than that which had been gained by the Allies from September 1914 till the beginning of the operation . Implications for Germany . By evacuating the Noyon and Bapaume salients , the German front was shortened by 25 miles , 14 German divisions were freed and Allied plans for the spring were seriously disrupted . The operation is considered to have been a propaganda disaster for Germany , due to the scorched earth policy but also one of the shrewdest defensive actions of the war . Implications for the Allies . During periods of fine weather in October 1916 , British reconnaissance flights had reported new defences being built far behind the Somme front ; on 9 November a formation of eight photographic reconnaissance aircraft and eight escorts reported a new line of defences , from Bourlon Wood – Quéant – Bullecourt – Sensée river – Héninel to the German third line near Arras . Two other lines closer to the front were observed as they were dug ( the " R . I " and " R . II " lines ) from Ablainzevelle – west of Bapaume – Roquigny and a branch from Achiet - le - Grand – Beugny – Ytres . Some authorities hold that British aerial reconnaissance failed to detect the construction of the Hindenburg line or the German preparations for the troop withdrawal . Beach ( 2004 ) concluded that evidence of German intentions had been collected but that German deception measures and the unremarkable nature of the information gleaned from intermittent air reconnaissance , caused by frequent bad flying weather over the winter and the fact that German digging of defences behind existing fortifications had taken place several times during the Somme battle led to British intelligence not interpreting the information accurately . In late December 1916 reports from witnesses led to British and French air reconnaissance further to the south . In mid - January 1917 British intelligence concluded that a new line was being built from Arras to Laon . By February the line was known to be near completion and that by 25 February the local withdrawals on the Fifth Army front and prisoner interrogation led to a gradual German withdrawal to the new line being anticipated . Their first intimation that a withdrawal had begun was when British patrols probing German outposts found them unoccupied . They then began a slow follow - up operation , but British unpreparedness , the destruction of all transport routes and the Germans ' natural advantage of falling back on their own prepared lines and use of well - positioned machine - gun nests in their rear , meant that the Germans completed an orderly withdrawal with minimal disruption . The British eventually found themselves facing a far more formidable German defensive position than they had after the Somme battles , as the Germans once again occupied all the higher and more strategically important positions while they occupied the lower ground facing when it came to the next Allied offensives in April , the British Battle of Arras and the French Nivelle Offensive .