Operation Alberich

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 the two salients which had been formed in 1916, between Arras and Saint-Quentin and from Saint-Quentin to Noyon, during the Battle of the Somme. 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 Erich 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 Siegfriedstellung (Hindenburg Line) was the best thing to do, since withdrawing might diminish the morale of German soldiers and civilians. 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. Ludendorff accepted the plan after representations 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 but lack of 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 40 – and require 13 fewer divisions. 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 and contemplated resignation but concluded that it might suggest a rift had developed between Bavaria and the rest of Germany.

Operation
The operation began on 9 February 1917 throughout the area to be abandoned. Railways and roads were dug up, trees were felled, water wells were polluted, towns and villages were destroyed and a large number of mines and other booby-traps were planted. About 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 4 March, General Louis Franchet d'Espèrey, commander of Groupe d'armées du Nord (GAN: northern army group), advocated an attack, while the Germans were preparing to retreat. Robert Nivelle, Commander-in-Chief of the French armies, approved only a limited attack, to capture the German front position and a possible opportunity significantly to upset the German withdrawal was lost. The withdrawal took place from 16–20 March, with a retirement of about 40 km, giving up more French territory than that gained by the Allies from September 1914, until the beginning of the operation.

Analysis
By evacuating the Noyon and Bapaume salients, the German front was shortened by 25 mi, 14 fewer German divisions were needed for line holding 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. 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 north to Quéant, Bullecourt, the Sensée river, Héninel and the German third line near Arras. Two other lines closer to the front were observed as they were dug ("R. I Stellung" and "R. II Stellung") from Ablainzevelle to west of Bapaume and Roquigny, with a branch from Achiet-le-Grand to Beugny and 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. In 2004, Beach 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 the British anticipating a gradual German withdrawal to the new line.

The first intimation that the British received that a withdrawal had begun, was when British patrols probing German outposts found them unoccupied. They then began a slow follow-up but unreadiness, the destruction of all transport routes and the Germans advantage of falling back on prepared lines, behind machine-gun nests, meant that the Germans completed an orderly withdrawal. 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 overlooked the lower ground facing, when it came to the next Nivelle Offensive in April.