World War I: Battle of Arras (1917)

On April 9, 1917, the Battle of Arras began. From the article:

"World War I: Battle of Arras (1917)

Background
After the bloodbaths at Verdun and the Somme, the Allied high command hoped to move forward with two offensives on the western front in 1917 with a supporting effort from the Russians in the east. With their situation deteriorating, the Russians pulled out of a combined operation in February leaving the French and British to proceed alone. Plans in the west were further disrupted in mid-March when the Germans conducted Operation Alberich. This saw their troops withdraw from the Noyon and Bapaume salients to the new fortifications of the Hindenburg Line. Conducting a scorched earth campaign as they fell back, the Germans succeeded in shortening their lines by approximately 25 miles and freeing up 14 divisions for other duty.

Despite the changes to the front brought about by Operation Alberich, the French and British high commands elected to move forward as planned. The main assault was to be led by General Robert Nivelle's French troops who would strike along the Aisne River with the goal of capturing a ridge known as Chemin des Dames. Convinced that the Germans had been exhausted by the previous year's battles, the French commander believed his offensive could achieve a decisive breakthrough and would end the war in forty-eight hours. To support the French effort, the British Expeditionary Force planned a push in the Vimy-Arras sector of the front. Scheduled to start a week earlier, it was hoped that the British attack would draw troops away from Nivelle's front. Led by Field Marshall Douglas Haig, the BEF began making elaborate preparations for the assault.

On the other side of the trenches, General Erich Ludendorff prepared for the expected Allied attacks by changing German defensive doctrine. Outlined in Principles of Command for Defensive Battle and Principles of Field Fortification, both of which appeared around the beginning of the year, this new approach saw a radical shift in German defensive philosophy. Having learned from German losses at Verdun the previous December, Ludendorff instituted a policy of elastic defense which called for the front lines to be held in minimum strength with counterattack divisions kept close at hand in the rear to seal off any breaches. On the Vimy-Arras front, the German trenches were held by General Ludwig von Falkenhausen's Sixth Army and General Georg von der Marwitz's Second Army.

The British Plan
For the offensive, Haig intended on attacking General Henry Horne's 1st Army in the north, General Edmund Allenby's Third Army in the center, and General Hubert Gough's Fifth Army in the south. Rather than firing on the entire front as in the past, the preliminary bombardment would be focused on a relatively narrow twenty-four-mile section and would last over a full week. Also, the offensive would utilize a vast network of underground chambers and tunnels that had been under construction since October 1916. Taking advantage of the region's chalky soil, engineering units had begun excavating an elaborate set of tunnels as well as connected several existing underground quarries. These would allow troops to approach the German lines underground as well as the placement of mines.

When completed, the tunnel system allowed for the concealment of 24,000 men and included supply and medical facilities. To support the infantry advance, BEF artillery planners improved the system of creeping barrages and developed innovative methods for improving counter-battery fire to suppress German guns. On March 20, the preliminary bombardment of Vimy Ridge commenced. Long a strongpoint in the German lines, the French had bloodily assaulted the ridge with no success in 1915. During the bombardment, British guns fired over 2,689,000 shells.

Moving Forward
On April 9, after a day's delay, the assault moved forward. Advancing in sleet and snow, British troops slowly moved behind their creeping barrage towards the German lines. At Vimy Ridge, General Julian Byng's Canadian Corps achieved stunning success and quickly took their objectives. The most carefully planned component of the offensive, the Canadians made liberal use of machine guns and after pushing through the enemy defenses reached the crest of the ridge around 1:00 PM. From this position, the Canadian troops were able to see down into the German rear area on the plain of Douai. A breakthrough may have been achieved, however, the attack plan called for a two-hour pause once objectives had been taken and darkness prevented the advance from continuing.

In the center, British troops attacked east from Arras with the goal of taking the Monchyriegel trench between Wancourt and Feuchy. A key section of the German defenses in the area, parts of the Monchyriegel were taken on April 9, however, it took several more days to completely clear the Germans from the trench system. British success on the first day was significantly aided by von Falkenhausen's failure to employ Ludendorff's new defensive scheme. Sixth Army's reserve divisions were stationed fifteen miles behind the lines, preventing them from rapidly advancing to block British penetrations.

Consolidating the Gains
By the second day, German reserves were beginning to appear and slowed British progress. On April 11, a two-division attack was launched against Bullecourt with the goal of widening the offensive on the British right. Moving forward the 62nd Division and Australian 4th Division were repulsed with heavy casualties. After Bullecourt, a pause in the fighting occurred as both sides rushed in reinforcements and built infrastructure to support the troops at the front. Over the first few days, the British had made dramatic gains including the capture of Vimy Ridge and advanced over three miles in some areas.

By April 15, the Germans had reinforced their lines across the Vimy-Arras sector and were prepared to launch counterattacks. The first of these came at Lagnicourt where they succeeded in taking the village before being compelled to retreat by the determined Australian 1st Division. Fighting resumed in earnest on April 23, with the British pushing east of Arras in an attempt to keep the initiative. As the battle continued, it turned into a grinding war of attrition as the Germans had brought reserves forward in all sectors and had strengthened their defenses.

Though losses were increasing rapidly, Haig was pressured to keep the attack going as Nivelle's offensive (begun April 16) was failing badly. On April 28-29, British and Canadian forces fought a bitter battle at Arleux in an attempt to secure the southeast flank of Vimy Ridge. While this objective was attained, casualties were high. On May 3, twin attacks were launched along the Scarpe River in the center and Bullecourt in the south. While both made small gains, losses led to the cancellation of both assaults on May 4 and 17 respectively. While fighting continued for a few more days, the offensive officially ended on May 23.

Aftermath
In the fighting around Arras, the British suffered 158,660 casualties while the Germans incurred between 130,000 to 160,000. The Battle of Arras is generally considered a British victory due to the capture of Vimy Ridge and other territorial gains, however, it did little to alter the strategic situation on the Western Front. Following the battle, the Germans built new defensive positions and a stalemate resumed. The gains made by the British on the first day were astounding by Western Front standards, but an inability to swiftly follow up prevented a decisive breakthrough. Despite this, the Battle of Arras taught the British key lessons regarding the coordination of infantry, artillery, and tanks which would be put to good use during the fighting in 1918."