Sulfur mustard later also against the French Second Army. The name Yperite comes from its usage by the German army near the town of Ypres. The Allies did not use mustard agent until November 1917 at Cambrai, France, after the armies had captured a stockpile of German mustard shells. It took the British more than a year to develop their own mustard agent weapon, with production of the chemicals centred on Avonmouth Docks. (The only option available to the British was the Despretz–Niemann–Guthrie process). This was used first in September 1918 during the breaking of the Hindenburg Line. Mustard agent was dispersed
Actions of 30 September – 4 October 1917 diary note that it had been an awful experience; he did not know what to do against the British. Erich Ludendorff the (Quartermaster-General of the German Army, equivalent to the British Chief of the General Staff) conferred on 29 September with (field marshal) Crown Prince Rupprecht the commander and (lieutenant-general) Hermann von Kuhl the chief of staff, of "Heeresgruppe Kronprinz Rupprecht von Bayern" (Army Group Rupprecht of Bavaria), the 4th Army commander, General Sixt von Armin and the 4th Army chief of staff, (major-general) Fritz von Loßberg. The staff officers of the 4th Army (corps headquarters) agreed that defensive manoeuvres