Operation Michael (German: Unternehmen Michael) was a major German military offensive during World War I that began the German spring offensive on 21 March 1918. It was launched from the Hindenburg Line, in the vicinity of Saint-Quentin, France. Its goal was to break through the Allied (Entente) lines and advance in a north-westerly direction to seize the Channel Ports, which supplied the British Expeditionary Force (BEF), and to drive the BEF into the sea, all before the Americans could arrive in full numbers to turn the tide of the war. Two days later, General Erich Ludendorff, the chief of the German General Staff, adjusted his plan and pushed for an offensive due west, along the whole of the British front north of the River Somme. This was designed to first separate the French and British Armies before continuing with the original concept of pushing the BEF into the sea. The offensive ended at Villers-Bretonneux, to the east of the Allied communications centre at Amiens, where the Allies managed to halt the German advance; the German Army had suffered many casualties and was unable to maintain supplies to the advancing troops.
Much of the ground fought over was the wilderness left by the Battle of the Somme in 1916. The action was therefore officially named by the British Battles Nomenclature Committee as The First Battles of the Somme, 1918, whilst the French call it the Second Battle of Picardy (2ème Bataille de Picardie). The failure of the offensive marked the beginning of the end of the First World War for Germany. The arrival in France of large reinforcements from the United States replaced Entente casualties but the German Army was unable to recover from its losses before these reinforcements took the field. Operation Michael failed to achieve its objectives and the German advance was reversed during the Second Battle of the Somme, 1918 (21 August – 3 September) in the Allied Hundred Days Offensive.
Background
Strategic developments
On 11 November 1917, the German High Command (Oberste Heeresleitung, OHL) discussed what they hoped would be a decisive offensive on the Western Front the following spring. Their target was the British Expeditionary Force (BEF), commanded by Field Marshal Sir Douglas Haig, which they believed had been exhausted by the battles in 1917 at Arras, Messines, Passchendaele and Cambrai. A decision to attack was taken by General Erich Ludendorff on 21 January 1918. At the start of 1918, the German people were close to starvation and growing tired of the war. By mid-February 1918, while Germany was negotiating the Russian surrender and the Treaty of Brest-Litovsk, Ludendorff had moved nearly 50 divisions from the east, so that on the Western Front, Germany's troops outnumbered those of the Allied armies. Germany had 192 divisions and three brigades on the Western Front by 21 March, out of 241 in the German Army. There were 110 of these divisions on the front line, and 50 of them faced the smaller British front. With 31 facing the BEF, there were 67 additional divisions in reserve. 318,000 American soldiers were expected in France by May 1918, and another million were expected by August. The Germans knew that the only chance of victory was to defeat the Allies before the build-up of the American Expeditionary Force (AEF) was complete.
The German strategy for the 1918 Spring Offensive or Kaiserschlacht (Kaiser's Battle), involved four offensives, Michael, Georgette, Gneisenau and Blücher–Yorck. Michael took place on the Somme and then Georgette was conducted on the Lys and at Ypres, which was planned to confuse the enemy. Blücher took place against the French in the Champagne region. Although British intelligence knew that a German offensive was being prepared, this far-reaching plan was much more ambitious than Allied commanders expected. Ludendorff aimed to advance across the Somme, then wheel north-west, to cut the British lines of communication behind the Artois front, trapping the BEF in Flanders. Allied forces would be drawn away from the Channel ports, which were essential for British supply; the Germans could then attack these ports and other lines of communication. The British would be surrounded and surrender.
The British Prime Minister, David Lloyd George, had agreed that the BEF would take over more of the front line, at the Boulogne Conference, against military advice, after which the British line was extended. The "line", taken over from the French, barely existed, needing much work to make it easily defensible to the positions further north, which slowed progress in the area of the Fifth Army (General Hubert Gough). During the winter of 1917–1918, the new British line was established in an arc around St. Quentin, by many small unit actions among the ruined villages in the area. There were many isolated outposts, gaps in the line and large areas of disputed territory and waste land. These positions were slowly improved by building the new three-zone system of defence in depth but much of the work was performed by infantry working-parties. Most of the redoubts in the battle zone were complete by March 1918 but the rear zone was still under construction.
The BEF had been reorganised due to a lack of infantry replacements; divisions were reduced from twelve to nine battalions, on the model established by the German and French armies earlier in the war. It was laid down that the senior regular and first-line territorial battalions were to be retained, in preference to the higher-numbered second-line territorial and New Army battalions. Second-line territorial and New Army divisions were badly disrupted, having in some cases to disband half of their battalions, to make way for units transferred from regular or first-line territorial divisions. Battalions had an establishment of 1,000 men but some had fewer than 500 men, due to casualties and sickness during the winter.
Tactical developments
The German army trained using open-warfare tactics which had proved effective on the Eastern Front, particularly at the Battle of Riga in 1917. The Germans had developed stormtrooper (Stoßtruppen) units, elite infantry which used infiltration tactics, operating in small groups that advanced quickly by exploiting gaps and weak defences. Stoßtruppen bypassed heavily defended areas, which follow-up infantry units could deal with once they were isolated, and occupied territory rapidly to disrupt communication by attacking enemy headquarters, artillery units and supply depots in the rear. Each division transferred its best and fittest soldiers into storm units, from which several new divisions were formed. This process gave the German army an initial advantage in the attack but meant that the best troops would suffer disproportionate casualties, while the men in reserve were of lower quality.
Developments in artillery tactics were also influential. Ludendorff was able to dispense with slow destructive and wire-cutting bombardments by using the large number of artillery pieces and mortars to fire "hurricane" bombardments concentrated on artillery and machine-gun positions, headquarters, telephone exchanges, railways and communication centres. There were three phases to the bombardment: a brief fire on command and communications, then a destructive counter-battery bombardment and then bombardment of front-line positions. The deep bombardment aimed to knock out the opponent's ability to respond; it lasted only a few hours to retain surprise, before the infantry attacked behind a creeping barrage. Such artillery tactics had been made possible by the vast numbers of accurate heavy guns and large stocks of ammunition that Germany had deployed on the Western Front by 1918.
An officer of the 51st (Highland) Division wrote: "The year 1917 ... closed in an atmosphere of depression. Most divisions on the Western front had been engaged continuously in offensive operations ... all were exhausted ... and weakened." The last German offensive on the Western Front, before the Cambrai Gegenschlag (counter-stroke) of December 1917, had been against the French at Verdun, giving the British commanders little experience in defence. The development of a deep defence system of zones and trench lines by the Germans during 1917, had led the British to adopt a similar system of defence in depth. This reduced the proportion of troops in the front line, which was lightly held by snipers, patrols and machine-gun posts and concentrated reserves and supply dumps to the rear, away from German artillery. British divisions arranged their nine infantry battalions in the forward and battle zones according to local conditions and the views of commanders; about 1⁄3 of the infantry battalions of the Fifth Army and a similar number in the Third Army held the forward zone.
The Forward Zone was organised in three lines to a depth depending on the local terrain. The first two lines were not held continuously, particularly in the Fifth Army area, where they were in isolated outpost groups in front of an irregular line of supporting posts. The third line was a series of small redoubts for two or four platoons. Posts and redoubts were sited so that intervening ground could be swept by machine-gun and rifle-fire or from machine-guns adjacent to the redoubts. Defence of the Forward Zone depended on fire-power rather than large numbers of troops but in the Fifth Army area a lack of troops meant that the zone was too weak to be able to repulse a large attack. The Battle Zone was also usually organised in three defensive systems, front, intermediate and rear, connected by communication trenches and switch lines, with the defenders concentrated in centres of resistance rather than in continuous lines. About 36 of the 110 infantry and pioneer battalions of the Fifth Army held the Forward Zone. Artillery, trench mortars and machine-guns were also arranged in depth, in positions chosen to allow counter-battery fire, harassing fire on transport routes, fire on assembly trenches and to be able to fire barrages along the front of the British positions at the first sign of attack. Artillery positions were also chosen to offer cover and concealment, with alternative positions on the flanks and to the rear. About 2⁄3 of the artillery was in the Battle Zone, with a few guns further forward and some batteries were concealed and forbidden to fire before the German offensive began.
Prelude
German plan of attack
The Germans chose to attack the sector around St. Quentin taken over by the British from February–April 1917, following the German withdrawal to the Hindenburg Line.
The attacking armies were spread along a 69-kilometre (43 mi) front between Arras, St. Quentin and La Fère. Ludendorff had assembled a force of 74 divisions, 6,600 guns, 3,500 mortars and 326 fighter aircraft, divided between the 17th Army (Otto von Below), 2nd Army (Georg von der Marwitz) of Heeresgruppe Kronprinz Rupprecht (Army Group Rupprecht of Bavaria) and the 18th Army (General Oskar von Hutier), part of Heeresgruppe Deutscher Kronprinz (Army Group German Crown Prince) and the 7th Army. The main weight of attack was between Arras and a few kilometres south of St. Quentin, where the 18th Army had 27 divisions. Forty-four divisions were allocated to Operation Michael and called mobile divisions, which were brought up to full strength in manpower and equipment. Men over 35 years old were transferred, a machine-gun unit, air support and a communications unit were added to each division and the supply and medical branches were re-equipped but a chronic shortage of horses and fodder could not be remedied. Around the new year the mobile divisions were withdrawn for training in the latest German attack doctrine.
Training emphasised rapid advance, the silencing of machine-guns and maintaining communication with the artillery, to ensure that infantry and the creeping barrage moved together. Infantry were issued with light machine-guns, mortars and rifle grenades and intensively trained. Thirty divisions were trained in the new tactics but had a lower scale of equipment than the elite divisions and the remainder were stripped of material to supply them, giving up most of their remaining draught animals. In the north, two German armies would attack either side of the Flesquières salient, created during the Battle of Cambrai. The 18th Army, transferred from the Eastern Front, planned its attack either side of St. Quentin, to divide the British and French armies. The two northern armies would then attack the British position around Arras, before advancing north-west to cut off the BEF in Flanders. In the south, it was intended to reach the Somme and then hold the line of the river against any French counter-attacks; the southern advance was extended to include an advance across the Somme.
British defensive preparations
In the north, the Third Army (General Julian Byng), defended the area from Arras south to the Flesquières Salient. To the south, the Fifth Army (General Hubert Gough) held the line down to the junction with the French at Barisis. The Fifth Army held the longest front of the BEF, with twelve divisions and three cavalry divisions, 1,650 guns, 119 tanks and 357 aircraft. An average British division in 1918 consisted of 11,800 men, 3,670 horses and mules, 48 artillery pieces, 36 mortars, 64 Vickers heavy machine guns, 144 Lewis light machine-guns, 770 carts and wagons, 360 motorcycles and bicycles, 14 trucks, cars and 21 motorised ambulances.