Outside the small town of Ipres in southwestern Belgium, there was a prominent Allied front, which, in order to destroy it, also wanted to test the power of the gas bombs that the Germans had just developed, and the Germans dropped poison gas bombs on a large scale from April to May 1915. It was also the only German offensive to the Southwest in 1915 and successfully destroyed two-thirds of the protruding front outside Ipres.
The German leadership was determined to crush Russia once and for all in 1915, so they were happy to remain on the defensive position on the Western Front in order to maximize the satisfaction of the eastern front. The British had just finished their offensive at Nouvelle Chapelle (10-13 March) and the French had only just emerged from the battle on the Plains of Wawour (6-15 April). However, Britain and France did not seem to care, and the opponent began to plan a new round of attack.
Upon learning of this news, General von Falkingham, chief of the General Staff of the German High Command, granted his troops on the Western Front to take the initiative in moderation in mid-spring. The German target was Ipres, and the British occupied a german position east of the town after the 1914 battle. However, the Germans wanted to clear the enemy from this position, occupy a high ground there that was very topographical, and then try out their new weapon here, the chlorine bomb.
The battle was fought by the German Fourth Army under Duke Albrecht of Württemberg. On 22 April, the fighting began with a burst of shelling. After a brief barrage attack, the Germans dropped a large number of chlorine bombs into the Allied positions. Chlorine ran out of the jar with a hiss, and soon filled the trenches where the French and Algerian armies were located, and countless Allied soldiers died of extreme pain due to suffocation. The defenders, who were not prepared for this, panicked and fled to save their lives, so the Allied defense line was quickly opened by the Germans.
The next day, the Germans advanced 3.2 kilometers wearing the most primitive gas masks, but their advance plans were severely hampered by a fierce counterattack by the British Second Army led by Smith Dorian.
But the British Second Army, despite its stubborn resistance, only gave the Allied army a chance to breathe. On the 24th, the Germans launched another attack with the Canadian forces northeast of Ipres, causing the fighting to spread rapidly to the east and southeast of the town, burning all the way to the Allied positions on Hill 60. In Smith Dorian's view, trying to regain lost ground at this moment is definitely not worth the loss. Therefore, he applied to lead his troops to withdraw from the more defensive area near Ipres. However, Field Marshal Frunche, commander-in-chief of the British Expeditionary Force, rejected the application and asked Herbert Plummer to take over Smith Dorian's job. Although General Herbert agreed that retreat was the best option, the withdrawal plan was not approved until 29 April when french resistance failed. In early May, the Allies regrouped their armies, and the poison gas war lasted until the 25th of that month.
In the final weeks of the battle, the Dukes of Albrecht's army, which had regained some of its positions, was gradually weakened, and by 8 and 14 May, its endurance had finally reached its limit. By this time, a 3.2-kilometre-long high ground defense line outside Ipres had been captured by the Germans, overlooking the shattered city of Ipres – a tragic sight that would continue until the Battle of Paschheimer in 1917.
During the month-long battle, the Germans occupied two-thirds of the prominent front, inflicting about 60,000 casualties on the Allies. The battle ended because the Germans were completely exhausted in manpower and material resources, and it was impossible to continue the offensive. However, the Germans continued to shell Ipres after the battle, almost leveling the remaining towns, and the British and French troops who held the remaining positions were tortured to death.