The Second Battle of Ypres was the first time Germany used poison gas on a large scale on the Western Front in World War I and the first time a former colonial force (Canadians) pushed back a major European power (Germans) on European soil, which occurred in the battle of St. Julien-Kitcheners' Wood.
The Second Battle of Ypres consisted of four separate engagements:
The scene of the battles was the Ypres salient where the Allied line which followed the canal bulged eastward around the town of Ypres, Belgium. North of the salient were the Belgians; covering the northern part of the salient itself were two French divisions (one Metropolitan and one Algerian) The eastern part of the salient was defended by one Canadian division and two UK divisions.
In total during the battles, the British Commonwealth forces were the II and V Corps of the Second Army made up of the 1st, 2nd and 3rd Cavalry divisions, and the 4th, 27th, 28th, 50th, Lahore and 1st Canadian Divisions.
With the survivors abandoning their positions en masse, a gap was left in the front line. However, the German High Command had not foreseen the effectiveness of their new weapon, and so had not put any reserves ready in the area. German troops started to enter the gap at 5:00PM in some numbers, but with the coming of darkness and the lack of follow up troops the German forces did not exploit the gap, and British and Canadian troops were able to put in a hasty defence that held that part of the line against further attacks until 3 May 1915 at a cost of 6000 wounded or dead. Casualties were especially heavy for the 13th Battalion CEF, which was enveloped on three sides and over-extended by the demands of security its left flank once the Algerian Division had broken.
One thousand of these "original" troops were killed and 4,975 were wounded from an initial strength of 10,000.
At Kitcheners' Wood, the 10th Battalion of the 2nd Canadian Brigade was ordered to counter-attack into the gap created by the gas attack. They formed up after 11:00pm on the night of 22 April with the 16th Battalion (Canadian Scottish) of the 3rd Brigade arriving as they were forming, tasked to support the advance. Both battalions stepped off with over 800 men, formed up in waves of two companies each, at 11:46 pm. Without prior reconnaissance, the battalions ran into obstacles half way to the objective and drew heavy automatic weapons fire from the Wood, prompting an impromptu bayonet charge. Their attack cleared the former oak plantation of Germans at the cost of 75 percent casualties.
The village of St. Julien had been comfortably in the rear of the 1st Canadian Division until the poison gas attack of 22 April, whereupon it became the front line. Some of the first fighting in the village involved a hasty defence, which included the stand of Lance Corporal Fred Fisher of the 13th Battalion CEF's machine-gun detachment; who twice went out with a handful of men and a Colt Machine-gun and prevented advancing German troops from passing through St. Julien into the rear of the Canadian front line. Fisher was awarded the VC for his actions on the 22nd, but was killed when he attempted to repeat his actions on the 23; this was the first of 70 Canadian VCs awarded in the First World War.
On the morning of 24 April 1915 the Germans released another cloud of chlorine gas, this time directly towards the re-formed Canadian lines just west of the village of St. Julien. On seeing the approach of the greenish-grey gas cloud, word was passed among the Canadian troops to urinate on their handkerchiefs and place these over their noses and mouths.
However, the countermeasures were ineffective and the Canadian lines broke as a result of the attack, allowing German troops to take the village.
The following day the York and Durham Brigade units of the Northumberland Division counterattacked failing to secure their objectives but establishing a new line close to the village. The third day the Northumberland Brigade attacked again, briefly taking part of the village but forced back with the loss of more than 1,900 men and 40 officers - two thirds of its strength.
The 2nd Royal Dublin Fusiliers Battalion suffered heavily, incurring hundreds of casualties and with no respite took part in the next two subsidiary battles at Frezenberg and Bellewaarde. On 24 May the battalion was subject to a German chlorine gas attack near Saint-Julien and effectively disintegrated as a fighting unit.
The surprise use of poison gas was not a historical first (poison gas had already been used on the Eastern Front) but did come as a tactical surprise to the Allies. After Second Ypres, both sides developed more sophisticated gas weapons, and countermeasures, and never again was the use of gas either a surprise, nor especially effective. The British quickly developed their own gas attacks using them for the first time at the Battle of Loos in late September. Development of gas protection was instituted and the first examples of the PH helmet issued in July 1915.
The Canadian Division was forced to absorb several thousand replacements shortly afterwards, but presented a most favourable image to their allies and the world. Another Canadian division joined the British Expeditionary Force in late 1915, joined eventually by two more in 1916. The battle also blooded many commanders, singling out some for praise, such as brigade commander Arthur Currie, and others for criticism, such as Garnet Hughes.
The inadequacies of training and doctrine in the early CEF was made obvious by the antique tactics used at Kitcheners' Wood and St. Julien, though tactics in the British Colonial armies would be slow to evolve. At Second Ypres, the smallest tactical unit in the infantry was a company; by 1917 it would be the section. The Canadians were employed offensively later in 1915, but not successfully.
A Third Battle of Ypres, more commonly known as Passchendaele was fought in the autumn of 1917. The battle was marked by Canadian tactical successes as a result of many innovations in organization, training and tactics in both the infantry and artillery.