On 28 May 1916, Byng took command of the Canadian Corps from Lieutenant-General Sir Edwin Alderson. Discussions for a spring offensive near Arras began, following a formal conference of corps commanders held at the First Army Headquarters (HQ) on 21 November 1916. In March 1917, the army HQ formally presented Byng with orders giving Vimy Ridge as the Canadian Corps objective for the Arras Offensive.

A plan, adopted in early March 1917, drew on the briefings of staff officers sent to learn from the experiences of the French Army during the Battle of Verdun. For the first time the four Canadian divisions would fight together. The nature and size of the attack needed more resources than the Canadian Corps possessed and the British 5th Division, artillery, engineer and labour units were attached to the corps, bringing the nominal strength of the Canadian Corps to about 170,000 men, of whom 97,184 were Canadian.
In January 1917, three Canadian Corps officers accompanied other British and Dominion officers attending lectures by the French Army on their experiences during the Battle of Verdun. The French counter-offensive devised by General Robert Nivelle had been one of a number of Allied successes of 1916. Following extensive rehearsal, eight French divisions had assaulted German positions in two waves along a 6 mi (10 km) front. Supported by extremely powerful artillery, the French had recovered lost ground and inflicted severe casualties on five German divisions.

On their return from the lectures, the Canadian Corps staff officers produced a tactical analysis of the Verdun battles and delivered corps and divisional-level lectures to promote the primacy of artillery and stress the importance of harassing fire and company and platoon flexibility. The report of the 1st Canadian Division commander, Arthur Currie, highlighted the lessons he believed the Canadian Corps could learn from the experiences of the French. The final plan for the assault on Vimy Ridge drew on the experience and tactical analysis of the officers who attended the Verdun lectures. The First Army commander, General Henry Horne approved the plan on 5 March 1917.

The plan divided the Canadian Corps advance into four coloured objective lines. The attack would be made on a front of 7,000 yd (4 mi; 6 km), with its centre opposite the village of Vimy, to the east of the ridge. The first objective, the Black Line, was the German forward defensive position. The final objective of the northern flank was the Red Line, taking the highest point on the ridge, the fortified knoll known as the Pimple, la Folie Farm, the Zwischen-Stellung (intermediate position) and the hamlet of Les Tilleuls. The southern two divisions were to achieve two …

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German 6th Army commander General Ludwig von Falkenhausen was responsible for the Cambrai–Lille sector and commanded 20 divisions, plus reserves. Vimy Ridge itself was principally defended by the ad hoc Gruppe Vimy formation based under I Bavarian Reserve Corps commander General der Infanterie Karl von Fasbender. However, a division of Gruppe Souchez, under VIII Reserve Corps General of the Infantry Georg Karl Wichura, was involved in the frontline defence along the northernmost portion of the ridge.

Three divisions were responsible for manning the frontline defences opposite the Canadian Corps. The 16th Bavarian Division was located opposite the village of Souchez and responsible for the defence of the northernmost section of the ridge. The division had been created in January 1917 by amalgamating existing Bavarian formations and had so far only opposed the Canadian Corps. The 79th Reserve Division was responsible for the defence of the vast central section, including the highest point of the ridge, Hill 145. The 79th Reserve Division had fought for two years on the Eastern Front before being transferred to the Vimy sector at the end of February 1917. The 1st Bavarian Reserve Division had been in the Arras area since October 1914 and held the villages of Thélus, Bailleul and the southern slope of the ridge.

Byng commanded four attacking divisions, one division in reserve and numerous support units. He was supported to the north by the 24th Division, I Corps, which advanced north of the Souchez River and by the XVII Corps to the south. The 4th Canadian Division was responsible for the northern portion of the advance that included the capture of the highest point of the ridge, followed by the elaborately fortified Pimple just west of the village of Givenchy-en-Gohelle. The 3rd Canadian Division was responsible for the narrow central section of the ridge, including the capture of La Folie Farm. The 2nd Canadian Division, which later included a brigade from the 5th Division, was directly south of the 3rd Canadian Division and entrusted with the capture of the village of Thélus. The 1st Canadian Division was responsible for the broad southern sector of the corps advance and expected to cover the longest distance. Byng planned for a healthy reserve for contingencies that included the relief of forward troops, help in consolidating positions and aiding the 4th Canadian Division with the capture of the Pimple. As a result, the 9th Canadian Brigade and the British 15th and 95th Brigades were kept in corps reserve.
Foreign intelligence gathering by the Germans, big Allied trench raids and troop concentrations seen west of Arras, made it clear to the Germans that a spring offensive in the area was being prepared. In February 1917, a German-born Canadian soldier deserted and helped confirm many of the suspicions held by t…

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By nightfall on 12 April 1917, the Canadian Corps was in firm control of the ridge, having suffered 10,602 casualties; 3,598 men had been killed and 7,004 wounded. The 6th Army casualties were not known at first in the disorganisation after the defeat. Later sources state around 20,000 casualties, German historians credit the high number of German casualties to Canadian and British artillery. Approximately 4,000 men were taken prisoner. The German Historical Service estimated that the 6th Army suffered 79,418 casualties during April and May 1917, 22,792 were classified as missing. Crown Prince Rupprecht estimated 85,000 casualties for the 6th Army, with 3,404 men taken prisoner at Vimy Ridge. Losses of the 79th Reserve Division from 1 to 11 April were 3,473 and in the 1st Bavarian Reserve Division 3,133. Casualties from the bombardment amongst reinforcements and Eingreif divisions are additional.

Following the defeat, the chief of the German General Staff, Field Marshal Paul von Hindenburg, ordered Oberste Heeresleitung (OHL, Supreme Army Command) to conduct a court of enquiry into the defensive collapse of the Arras sector. The court concluded that the 6th Army headquarters had disregarded reports from commanders in the front line noting a possible imminent attack and reserve units were too distant to counter-attack before the Canadians could consolidate. The court concluded that 6th Army commander General Ludwig von Falkenhausen failed to apply an elastic defence according to German defensive doctrine. Instead, the defensive system comprised strong points and lines of resistance, which the Allied artillery had isolated and destroyed. Hindenburg removed Falkenhausen from his command and transferred him to Belgium, where he served the remainder of the war as governor-general.

The Germans did not see the capture of Vimy Ridge by the Canadian Corps as a loss. Contemporary German sources viewed the action, at worst, as a draw, given that no breakthrough occurred following the attack. The Germans did not attempt to recapture the ridge, even during the Spring Offensive, and it remained under British control until the end of the war. The loss of Vimy Ridge forced the Germans to reassess their defensive strategy in the area. Instead of mounting a counterattack, they pursued a scorched earth policy and retreated to the Oppy–Méricourt line. The failure of the French Nivelle Offensive in the week after the Arras Offensive placed pressure on Field Marshal Douglas Haig to keep the Germans occupied in the Arras sector to minimize French losses. The Canadian Corps participated in several of these actions including the Battle of Arleux and the Third Battle of the Scarpe in late April and early May 1917. After the end of the …

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