Battle of Hill 70 The Battle of Hill 70 was a localized battle of World War I between the Canadian Corps and five divisions of the German Sixth Army . The battle took place along the Western Front on the outskirts of Lens in the Nord - Pas - de - Calais region of France between 15 August 1917 and 25 August 1917 . The primary objective of the assault was to inflict casualties and draw German troops away from the 3rd Battle of Ypres , rather than to capture territory . To achieve this objective , The Canadian Corps executed a limited operation to occupy the high ground at Hill 70 quickly , establish defensive positions and utilize combined small arms and artillery fire , some of which used the technique of predicted fire for the first time , to repel German counterattacks and inflict as many casualties as possible . A later attempt by the Canadian Corps to extend its position into the city of Lens itself failed . The Canadians and the Germans both suffered high casualty rates , and Lens remained under German control . The German assessment of the battle was that it succeeded in its attritional objective . The battle consisted of extensive use of poison gas by both sides , including the newly introduced German Yellow Cross shell containing the blistering agent sulfur mustard . Ultimately , the goals of the Canadian Corps were only partially accomplished . The Canadians were successful in preventing German formations from transferring local men and equipment to aid in defensive operations in the Ypres Salient but failed to draw in troops from other areas . Background . The industrial coal city of Lens , France had fallen under German control in October 1914 during the Race to the Sea . Consequently , the Germans also controlled the heights at Hill 70 to the north of the city and Sallaumines Hill to the southeast , both of which had commanding views over the surrounding area as well as the city itself . Hill 70 was a treeless expanse at the end of one of the many spurs . In September 1915 , the British had overrun the hill during the Battle of Loos but had not managed to hold it . British First Army commander General Henry Horne ordered the Canadian Corps to relieve I Corps from their position opposite the city of Lens on 10 July 1917 and directed Canadian Corps commander Arthur Currie to develop a plan for capturing the town by the end of July 1917 . The operation was intended to engage as many German formations as possible and to prevent them from reinforcing the Ypres sector during the Third Battle of Ypres . Command of the Canadian Corps had only recently changed . A month earlier , Canadian Corps commander Julian Byng was promoted to the rank of General and replaced General Edmund Allenby as commander of the British Third Army . In turn , 1st Canadian Division commander Arthur Currie was promoted to the rank of Lieutenant - General and assumed command of the Canadian Corps . Tactical plan . Currie regarded control of either Hill 70 or Sallaumines Hill as tactically more important than control of the city of Lens . Merely to occupy the city while the Germans held the high ground would place the attackers in an unfavourably lower and more exposed position than the ones they currently occupied . At a conference of corps commanders , Currie persuaded the First Army commander General Henry Horne to make Hill 70 , not the city of Lens , the main objective of the limited offensive . Controlling Hill 70 would provide excellent observation over the German lines , in preparation for any future offensives . Currie believed the Germans would attempt to counterattack if Hill 70 were captured , largely because of its observational importance . Nevertheless , Currie believed that the advantageous observational position of Hill 70 would permit well directed artillery to effectively deal with any counterattacks . The plan was therefore to occupy the high ground quickly , establish defensive positions , and utilize combined small arms and artillery fire to repel expected counterattacks and inflict as many casualties as possible . In an attempt to further deceive the Germans , minor operations were conducted in an effort to suggest a forthcoming attack by the British First Army south of La Bassée canal . This included an attack by the 9th Canadian Brigade against units of the German 36th Reserve Division at Mericourt trench and a British First Army poison gas attack north of Loos , both in late July 1917 . Bad weather led to the postponement of the attack on Hill 70 from late July until mid - August . In the interim , special companies of the Royal Engineers augmented the regular level of harassment by firing a total of drums and shells into Lens by 15 August . The artillery neutralized of an estimated batteries in the area by zero hour , partly with the technique of predicted fire for the first time , using datum points and calibrated guns , which greatly improved the accuracy of artillery fire . Troops were rotated through the reserve area to conduct training and rehearsals in preparation for the assault . These obvious preliminary actions to an attack did not go unnoticed by the Germans , which made it impossible to conceal the First Army ' s general intentions or even , as it turned out , the date of the assault . The best that could be done was to attempt to mislead the Germans with respect to exact time and place . To this end I Corps staged exercises with dummy tanks on 14 August , directly west of Lens . The battle . Opposing Forces . Canadian Corps commander Lieutenant - General Arthur Currie had three attacking divisions , one division of reserves and numerous support units under his command . German Sixth Army commander " General der Infanterie " Otto von Below was responsible for the area between Lille and Cambrai . Hill 70 , and the area surrounding it was defended by the ad hoc . The defending elements of the German Sixth Army consisted of the 7th Infantry Division , 4th Guards Infantry Division , 185th Infantry Division , 11th Reserve Division and 220th Infantry Division . Assault on Hill 70 . The plan to capture Hill 70 called for 1st and 2nd Canadian Divisions to attack on a front of . Their objective was to capture the main enemy defensive positions on the eastern or reverse slope of Hill 70 . The objectives were marked off in depth by three stages . In the first stage , the assaulting troops would capture the German front - line trenches . The German second position on the crest of the hill during the second stage and the final stage , marked by the German third line , on the reverse side of the slope , some from the starting position . The 1st Canadian Division ' s 3rd Canadian Infantry Brigade would attack north of Hill 70 while the 2nd Canadian Infantry Brigade would attack the summit itself . The 2nd Canadian Division ' s 4th and 5th Canadian Infantry Brigades would attack the rubble remains of the suburbs of Cité St . Édouard , St . Laurent and St . Émile directly south of Hill 70 . The assault began at on the morning of 15 August , just as dawn was breaking . Special companies of the Royal Engineers fired drums of burning oil into the suburb of Cité St . Élisabeth and at other selected targets in order to supplement the artillery rolling barrage and build up a smoke - screen . Divisional field artillery positions executed a rolling barrage directly in advance of the assaulting troops while field howitzers shelled German positions 400m in advance of the rolling barrage and heavy howitzers shelled all other known German strong - points . Artillery Forward Observation Officers moved forward with the infantry and artillery observation aircraft flew overhead and sent for artillery fire by wireless . The Germans had moved up their reserve units on the previous night in anticipation of an attack . The main assembly of Canadian troops was detected by and within three minutes of the attack commencing the German artillery brought down defensive fire at widely scattered points . The affected forward positions of the German 7th Division and 11th Reserve Division were quickly overwhelmed . Within twenty minutes of the attack beginning , both Canadian Divisions had reached their first objective . By the 2nd Canadian Infantry Brigade had reached the second objective line while units in the other three brigade had in some cases already reached their final objective . However , only the flanking companies of the two battalions attacking Hill 70 itself managed to reach their objectives . The remainder of the both units were forced to retreat up the slope and consolidate their position at intermediate objective line . On the right flank of the 2nd Canadian Division , the 12th Canadian Infantry Brigade of the 4th Canadian Division executed a diversionary operation which proved successful in drawing German retaliatory fire away from the main operation . Four hours later , the 11th Canadian Infantry Brigade of the 4th Canadian Division attempted to exploit the weaken German force by pushing strong patrols towards the centre of Lens . This ultimately proved unsuccessful as the Germans used local counterattacks across the 4th Canadian Division ' s front to drive the patrols back to the city ' s outskirts . Initial counterattacks . In preparation for German counterattacks , the 1st and 2nd Canadian Divisions began to reinforce and construct strong points immediately after capturing the first objective line . Within two hours of the start of the battle the Germans began using their immediate reserves to mount local counterattacks . Between on the morning of the 15th , the Germans executed four local attacks against Canadian positions . Each attack was repulsed due in large part to the work of forward artillery observers who could now overlook some of the German positions . However , in at least one instance the counterattack was only repulsed after engaging in hand - to - hand fighting . The Germans rapidly brought up seven additional battalions from the 4th Guards Division and 185th Division to reinforce the eight line battalions already in place . Over the following three days , the Germans executed no less than 21 counterattacks against Canadian positions . A frontal attacks against the 2nd Canadian Infantry Brigade on the afternoon of 15 August ultimately failed . A German attack against the 4th Canadian Infantry Brigade was initially successful with the Germans re - capturing Chicory Trench but were repulsed later the same afternoon . Capture of Hill 70 and additional counterattacks . The morning of 16 August was relatively quiet , with only a few attempts made by small German parties to approach the Canadian lines . After having failed to capture all their objectives the previous day and having postponed additional attacks a number of times , the 2nd Canadian Brigade attacked and captured the remainder of its final objective line on the afternoon of 16 August . The assault lasted a little over an hour but the troops were then forced to defend against a dozen German counterattacks during the day . Attempts by the 4th and 11th Canadian Infantry Brigades to eliminate an enemy salient between Cité St . Élisabeth and Lens on 17 August failed and as had been foreseen the Germans continued to mount determined counterattacks . The German command began to realize that the Canadian and British artillery would need to be neutralized before any counterattacks would be successful . The Germans began a series of counterattacks against a chalk quarry under Canadian control outside of Cité St . Auguste but also sought to wear down the Canadian artillery resources by sending up false flare signals or provoking the infantry to call for unnecessary artillery fire . The Germans also began to use poison gas in earnest . From the new Yellow Cross shells containing the blistering agent sulfur mustard were fired in addition to an undetermined number of shells containing diphosgene . The Canadian 1st and 2nd Artillery Field Brigades and the Canadian front line were heavily gassed . Many artillery men became casualties after gas fogged the goggles of their respirators and they were forced to remove their masks in order to set the fuses , lay their sights and maintain accurate fire . The Germans used the cover of gas to make a number of attempts against the Canadian controlled chalk quarry and Chicory Trench on the night of 17 August and early morning of 18 August . All attempts against the chalk quarry failed and only one company of the 55th Reserve Infantry Regiment ( on loan to the 11th Reserve Division ) managed to breach the Canadian defenses at Chicory Trench before being repulsed . German troops employing flamethrowers managed to penetrate the Canadian line north of the quarry on the morning of 18 August before being driven out . Attack on Lens . The front quieted significantly after the final attack against the chalk quarry . For the Canadian Corps , the following two days consisted largely of consolidation activities . The front line was drawn back , midway between the original intermediate and final objective lines and the 4th Division slightly advanced its forward posts on the outskirts of Lens and extended its front northward to include the Lens – Bethune road . Currie however wish to further improve the position around Hill 70 and ordered an attack against enemy positions along a front directly opposite the 2nd and 4th Canadian Divisions . The operation was scheduled for the morning of 21 August , the tasks being divided between the 6th Canadian Infantry Brigade , on the left , and the 10th Canadian Infantry Brigade on the right . The attack was to begin at however the German began shelling the Canadian positions at and just before the Canadian attack was set to launch the 6th Canadian Infantry Brigade ' s left flank was attack by units of the German 4th Guards Infantry Division . Both forces met between their respective objectives , and desperate hand - to - hand and bayonet fighting ensued . In the chaos the 6th Brigade ' s advance all but collapsed . Communications between the brigade ' s forward units and brigade headquarters had broken down at the beginning of the attack and could not be restored due to heavy German shelling , making it all but impossible to coordinate further actions of the assaulting units and the artillery . Counterattacks by the 4th Guards Division , reinforced by a battalion of the 220th Infantry Division ultimately forced any 6th Canadian Infantry Brigade units who had reached the objective line to retreat to the safety of the starting line . On the right flank , the 10th Canadian Infantry Brigade fared no better . One attacking unit suffered a large number of shellfire casualties while still assembling for the attack and were met the intense artillery and machine - gun fire as they neared their objective line . Only three small parties , the largest of not more than twenty men , reached their goal . The remaining two attacking units of the brigade managed to reach and capture their objectives but not until late in the evening . As a result of having only partially captured their intended objectives , a salient was created in the 4th Canadian Division ' s line . On the evening of 21 August an attempt was made to correct the situation by sending three parties to bomb the German position from the flanks but was only moderately successful . An additional attack planned for 22 August failed to materialize due to battalion - level misunderstandings . A brigade reserve unit was tasked with correcting the situation by attacking a slag heap called Green Crassier and the mine complex at Fosse St . Louis . The attack proved to be a miserable failure with the majority of the attackers being killed , wounded or taken prisoner . In the end the hotly disputed position was back in German possession and remained so until the German retreat towards the end of the war . Aftermath . Subsequent operations . The remainder of August , all of September and the beginning of October were relatively quiet , with Canadian efforts devoted mainly to preparations for another offensive . No further offensives took place however , largely because the British First Army lacked sufficient resources for the task . Instead , the Canadian Corps was transferred to the Ypres sector in early October in preparation for the Second Battle of Passchendaele . Soon after the battle , German Sixth Army commander Otto von Below was transferred to the Italian front , where he took command of the newly formed Austro - German 14th Army . In this capacity , he executed an extremely successful offensive at the Battle of Caporetto in October 1917 . Ferdinand von Quast took over command of the German Sixth Army until the end of the war . Analysis . The Germans refrained from attempts to recapture the lost ground at Lens , due to the demands of defensive operations of the Third Battle of Ypres and the need to avoid the diversion of forces from the main effort . Victoria Cross . Six Victoria Crosses , the highest military decoration for valour awarded to British and Commonwealth forces , were awarded to members of the Canadian Corps for their actions during the battle ;