Editing Battle of Vimy Ridge (section)

===Artillery===
[[File:Vimy Ridge 1917-barrage map.jpg|thumb|upright|Map showing rolling artillery barrage for advance]]
The eight field artillery brigades of the Canadian Corps divisional artillery and two heavy artillery groups were reinforced with British artillery units.{{sfn|Farndale|1986|p=238 Map 38}} Four heavy artillery groups, nine field artillery brigades, three divisional artillery groups and the artillery complement of the 5th Division was attached to the Canadian Corps. Ten heavy artillery groups of the flanking I and XVII Corps were assigned tasks in support of the Canadian Corps.{{sfn|Farndale|1986|p=238 Map 38}} The artillery batteries of [[I Corps (United Kingdom)|I Corps]] were particularly important because they enfiladed German gun positions behind Vimy Ridge.{{sfn|Chasseaud|1999|p=266}} The British provided twenty-four brigade artillery groups consisting of four hundred and eighty [[Ordnance QF 18 pounder|18&nbsp;pounder field guns]], one hundred and thirty-eight [[QF 4.5 inch Howitzer|4.5&nbsp;inch howitzers]], ninety-six [[2 inch Medium Mortar|2&nbsp;inch trench mortars]], twenty-four [[9.45 inch Heavy Mortar|9.45&nbsp;inch mortars]], supported by 245 siege guns and heavy mortars.{{sfn|Nicholson|1962|p=225}}{{sfn|Cook|2007|p=113}} This firepower gave a density of one heavy gun for every {{cvt|20|yd|-1|order=flip}} and one field gun for every {{cvt|10|yd|-1|order=flip}} of the corps frontage, representing a considerable average increase, including three times the heavy guns over the distribution of artillery at the Battle of the Somme in 1916.{{sfn|Nicholson|1962|p=225}}{{sfn|Sheffield|2002|pp=191, 194}}

On 8 February, the First Army issued a 3,000-word artillery plan devised by Horne and his principal artillery commander, Major General H. F. Mercer.{{sfn|Robbins|2010|p=164}} Brigadier-General [[Edward Morrison (Canadian Army officer)|Edward Morrison]] developed and issued a 35-page multi-phased fire support plan called ''Canadian Corps Artillery Instruction No.{{spaces}}1 for the Capture of Vimy Ridge'' to support the efforts of the infantry.<ref>WO 106/399 Canadian Corps Artillery Instruction No.&nbsp;1 for the Capture of Vimy Ridge (1917)</ref> The Canadian Corps received three times the artillery normally assigned to a corps for regular operations.{{sfn|Brennan|2007|pp=98–99}} To manage the supply of the extra guns, the Royal Artillery staff officer, Major [[Alan Brooke]], coordinated communication and transport plans to work with the barrage plans.{{sfn|Brennan|2007|pp=98–99}}

A 1.6{{spaces}}million shell allotment allowed the artillery along the Canadian Corps front to maintain a high rate of fire.{{sfn|Cook|2007|p=113}} Improvements in the quality of the shells ensured fewer [[dud]]s.{{sfn|Sheffield|2002|p=191}} The new instantaneous [[No. 106 fuze]] greatly improved the effectiveness of the artillery since this fuse burst reliably with the slightest of contact, unlike older timed fuses, making it especially effective at wire cutting before the advance.{{sfn|Cook|2007|p=113}} To maintain communications during the battle, particularly with the artillery, field units laid over {{cvt|1400|km|order=flip}} of telegraph and [[field telephone]] cabling, normally at a depth of {{cvt|7|ft}}.{{sfn|Turner|2005|p=39}} The corps conducted coordinated [[counter-battery]] shoots before the battle. The First Army Field Survey Company printed barrage maps for all batteries, produced artillery boards and provided counter-battery support with their flash spotting groups and [[sound ranging]] sections.{{sfn|Chasseaud|1999|p=268}} Using flash spotting, sound ranging and aerial reconnaissance from [[No. 16 Squadron RAF|16 Squadron]] and {{nowrap|1 & 2}} Balloon Companies [[Royal Flying Corps]] (RFC) in the week before the battle, the counter-battery artillery under command of Lieutenant-Colonel [[Andrew McNaughton]] fired 125,900 shells, harassing an estimated 83 per cent of the German gun positions.{{sfn|Cook|2007|p=117}}