Hundred Days Offensive 1918: Amiens and the Black Day of the German Army

The Hundred Days Offensive was the series of Allied attacks on the Western Front between 8 August and 11 November 1918 that broke the German army and forced the Armistice. It began at Amiens on 8 August, when British, Australian, Canadian and French troops advanced up to 11 km in a single day, took more than 12,000 prisoners and about 400 guns, and prompted General Ludendorff to call it "the black day of the German Army". Within three months the Hindenburg Line was broken and Germany asked for terms.

Why Amiens: the situation in August 1918

After the German Spring Offensive of 1918 failed to deliver a decisive victory, the German army was stretched across a long, newly won salient and exhausted by casualties. Every month about 250,000 fresh American soldiers were arriving in France, while Germany had no comparable reserves. Marshal Foch, Supreme Allied Commander, saw the moment to switch from defence to attack.

The Allied plan for Amiens was a surprise attack by the British Fourth Army under Rawlinson, led by the Australian Corps (General Monash) and the Canadian Corps (General Currie), with the French First Army on the right. Secrecy was the key: the Canadians were moved in by night, radio traffic was faked elsewhere, and the barrage was fired only when the infantry started to move.

8 August 1918: the black day

At 04:20 in dense morning fog, around 2,000 guns opened a short, precise barrage and more than 500 tanks rolled forward with infantry and armoured cars. Aircraft hit German batteries and airfields. The German front, held by tired and under-strength divisions, collapsed in several places.

By evening the Allies had advanced about 11 km, the deepest single-day gain on the Western Front since 1914. German losses were around 27,000 including more than 12,000 prisoners. What shocked Ludendorff most was not the lost ground but the way some German units surrendered. On 14 August, at Spa, the Kaiser concluded that the war could no longer be won and that a way out had to be found.

The tank success must not be exaggerated: within a few days most Mark V tanks were broken down or destroyed, and the attack slowed when it met prepared defences. That is exactly why Foch changed the method.

Foch's method: many blows, not one breakthrough

Instead of pushing one attack until it stalled, Foch ordered a chain of attacks along the whole front, each stopped as soon as resistance hardened, so that the Germans never had time to move reserves. The offensive went roughly in this order:

• 8 August: Amiens, Fourth Army and French First Army.
• 21 August: the Battle of Albert, Third Army, widening the breach.
• 26 August to 3 September: attacks at Arras, Canadian Corps on the Drocourt-Quéant line.
• 12 September: Americans reduce the St Mihiel salient.
• 26 September: the Meuse-Argonne offensive begins.
• 29 September: British Fourth Army breaks the Hindenburg Line at the St Quentin Canal.

The Americans and the collapse of the allies of Germany

The Meuse-Argonne offensive (26 September to 11 November, 47 days) was the largest American operation of the war, with around 1.2 million US soldiers. It was costly and slow, but it pinned down German divisions that could not be used elsewhere.

At the same time Germany's partners fell away: Bulgaria signed an armistice on 29 September, the Ottoman Empire on 30 October and Austria-Hungary on 3 November. On 29 September Ludendorff himself demanded that the government seek an armistice. At 11:00 on 11 November 1918, in a railway carriage in the forest of Compiègne, the guns finally stopped. For the full story of the end of the war, see how World War 1 ended.

What the Hundred Days teach a strategy player

The campaign is the best historical lesson in combined arms: infantry, artillery, tanks and aviation worked together instead of separately. In Frontkrieg the same ideas apply.

• Concentrate force on one weak sector instead of spreading armies thin.
• Combine unit types so that each covers the weakness of another.
• Stop an attack when it stalls and strike elsewhere, as Foch did.
• Keep your intentions hidden: scouting and fog of war decide who is surprised.

Our guide to offensive tactics in Frontkrieg shows how to apply this on the map. You can try it yourself for free in the lobby, and browse more articles on the blog. For the full chronology, see the World War 1 timeline.

FAQ

What was the Hundred Days Offensive?

It was the final Allied campaign of World War 1 on the Western Front, from 8 August 1918 to 11 November 1918, that pushed the German army back and ended in the Armistice.

Why is 8 August 1918 called the black day of the German Army?

Ludendorff used the phrase for the first day of the Battle of Amiens, when the Allies advanced about 11 km, captured over 12,000 prisoners and showed German morale was breaking.

Did the war really last only 100 days?

No. The name is approximate: from Amiens on 8 August to the Armistice on 11 November is about 95 days of continuous Allied offensive.

Who commanded the Allied armies?

Marshal Ferdinand Foch was Supreme Allied Commander, with Field Marshal Haig leading the British forces and General Pershing the American forces.

Further reading: Hundred Days Offensive on Wikipedia. Frontkrieg is free to play, with no pay-to-win, and is available in four languages.