THE Second Battle of the Marne had done more than ward off a peril. It had set the German command sparring for time. Yet Hindenburg and Ludendorff would not want a lot of time. They had decided to go over to the defensive, but were confident that they would be able to return to the offensive without a long delay. They had various projects in mind, but the favourite was still ‘Hagen’ in the region of Ypres, though this would now have to be somewhat reduced in scale. Their foes were thus given the opportunity to get a blow in first. It was a fateful moment in which much depended on the strength of that blow.
For the British the action of Hamel on 4 July afforded a nucleus of ideas, a small-scale model.1 The Fourth Army Commander, Rawlinson, was eager to expand it into a bigger offensive, with the tank as the predominant weapon. Haig agreed. The area, east of Amiens, appealed also to Foch, who attributed immense importance to the liberation of lateral lines of communication, broken by the German offensives. In this case the Amiens-Paris railway, well known to generations of British holiday-makers, was to be freed. The Germans were not actually sitting astride it, but south-east of the city they were less than four miles from it and Amiens itself came frequently under fire from heavy artillery. Foch directed the French First Army (Débeney) on the British right to take part in the operation and placed it under Haig’s orders; but only its two left-hand corps were to attack on the first day.
Then Foch went a step farther. He arranged that the French Third Army (Humbert) on the south side of the German salient should strike the enemy’s flank in aid of the First Army. He also demanded that the assault should be put forward two days, from 10 August to 8 August. That made a lot of work, but it was a welcome change, since practically every big offensive in the war was postponed. The objective was extended to the so-called Roye-Chaulnes line, actually the old, largely decayed, British entrenchments of February 1917, before the German retreat to the Hindenburg Line. This was a maximum distance of nearly fourteen miles.
The main blow was to be struck by the Canadian Corps (Currie). This magnificent body of troops, with many of its battalions two hundred over establishment and no immature men, had taken part in none of the defensive battles because Haig, to his annoyance, was not permitted to use its divisions under any corps commander but their own. It was brought in unobtrusively and none of its troops were permitted to enter the foremost trenches until the night preceding the attack. On its left was the Australian Corps (Monash), equally good troops of a rather different pattern, perhaps even cleverer tactically but at lower levels apt to be less careful of detail. The British contingent comprised the III Corps (Butler), as virtually a gigantic flank guard; the Cavalry Corps (Kavanagh); a reserve division; a mass of heavy, and a considerable amount of field, artillery; and a powerful armoured force of twelve tank battalions—324 heavy tanks, ninety-six light, and twelve armoured cars, not including reserves and older types converted to serve as supply vehicles. The United States 33rd Division was in reserve to the III Corps.
The French First Army began with three corps. So many tanks still remained on the Marne battlefield that only light ones were available, and Débeney judged that they were too few and fragile to be sent over in first line. They were indeed essentially weapons of exploitation. He attached them to divisions destined to take later objectives. Since his leading troops would thus have no armour he considered that a preliminary bombardment would be necessary. This in turn meant that the French First Army would not advance until after the British Fourth, which, on the pattern of Cambrai, was to go forward at the moment the artillery opened fire.
By the morning of 8 August the British had eleven divisions in first line or due to enter the fight on the first day and four in reserve. The French had ten; but their action was to develop from the left and only seven were to be engaged on 8 August. The R.A.F. had assembled 374 aircraft. The French strength was greater, but the Air Division did not come into action until the 9th. The corresponding front of the German Eighteenth Army (Hutier) and Second Army (Marwitz) mustered fourteen divisions against the twenty-one allied.