The Third Battle of the Aisne was the third major offensive launched by the Germans on the Western Front in the summer of 1918 (First World War). The first of those offensives, the Second Battle of the Somme, had come close to breaking the allied lines, threatening to split apart the British and French armies. The second, on the Lys River, had pushed the British line back, but had not had quite the same impact. Ludendorff then decided to launch a third attack on the French lines in the Chemin des Dames (Operation Blűcher-Yorck). This would threaten Paris, and hopefully force the allies to concentrate their reserves in front of the city. If that happened, then the Germans would launch a new attack against the weakened British lines to the north.
Despite being described as a diversion, Ludendorff assembled a massive army for the attack on the Aisne. Forty one divisions supported by as many as 6,000 guns (1st Army under General Bruno von Mudra and 7th Army under General von Boehn) were lined up against sixteen Allied divisions, three of which were British divisions moved south for a rest after the fighting further north (French 6th Army under General Duchêne).
The battle began with one of the most intense artillery bombardments of the war. The Germans fired some two million shells in four hours on the morning of 27 May and then launched their attack with seventeen divisions. The Allied lines on the Chemin des Dames were shattered. The Germans were able to advance thirteen miles on the first day of the battle, the single biggest advance since the beginning of trench warfare in 1914. The bridges across the Aisne were captured intact and the Germans began an advance towards the Marne.
The Allied response to this crisis was rather better organised than during the attack on the Somme. Twenty seven divisions were fed into the line between 28 May and 3 June. The German advance continued throughout May. Soissons was captured on 28 May. German troops crossed the Marne around Jaulgonne and on 30 May reached Château Thierry. German troops were now only thirty seven miles from Paris.
This was a close as they would get. The advancing German troops had outrun their supplies. They had lost over 100,000 men in the battle (as did the Allies), and by the start of June had lost much of their numerical advantage. The battle also saw the appearance of large numbers of American troops in the front line for the first time. On 1 June the American 3nd Division had taken up the defence of Château Thierry, before launched a counterattack that forced the Germans back across the Marne. They were followed into action by the 2nd Division, who on 6 June attacked the German positions at Belleau Wood, to the north west of Château Thierry.
Ludendorff would launch two more offensives during the summer of 1918 (Noyon-Montdidier in June and Champagne-Marne in July), but neither had the same impact as the Somme or Aisne offensives. The balance of power on the Western Front was about to move in favour of the allies. Ludendorff’s offensives had pushed the Allies back by up to thirty miles, but had failed to break the line, and had dramatically weakened the German army. The fifth and final of the German offensives ended with an allied offensive (Second Battle of the Marne) and was quickly followed by the battle of Amiens, which saw the first signs of a German collapse.