Each such mutual relief meant the movement of upwards of 20,000 men, and separate roads had to be allotted for their use. Frequently in so large a Corps as this, two such inter-divisional reliefs would synchronize or overlap, and the danger of congestion and the Staff work necessary to avoid it would be thereby more than doubled. And all this work would have to go on smoothly even if the Corps front were in the throes of an actual battle at the time.
Although much of the routine of such reliefs, which had become almost a ritual during the preceding years of trench warfare, was now scrapped, it is a matter of pride to the Australian Corps and its Divisions, that all such relief operations, even amid all the stress of these busy fighting months of August and September, were, until the end, carried out with precision, freedom from irritating hitches, and a minimum of stress on the troops.
The decisions which had to be given regarding the times and alternations of these Divisional reliefs became from now on really of basic importance, and affected the main framework of the whole of my future plans. It was no longer merely a question of earmarking certain Divisions for a specified single operation; but of planning, many days ahead, the rotation in which the Divisions were to be employed in a continuous series of operations. I regarded it as a fundamental principle to employ whenever possible absolutely fresh and rested troops for an operation of any magnitude or importance. To carry such a principle into effect involved the necessity of making the best surmise that was possible as to the course of events a week or even two weeks ahead.
As I shall endeavour to make clear in the course of the following pages, the really outstanding and exceptional features of the work of the Corps in its last sixty days were the sustained vigour of its fighting, and the unbroken continuity of its collective effort. Those results would clearly depend more on the manner in which the resources in troops were manipulated than upon any other factor. Each Division had to be kept employed until the last ounce of effort, consistent with speedy recovery, had been yielded, and each Division had to rest a sufficient time to enable it fully to recover its spirit and tone, and yet had to be ready by the time it was wanted.
The fulfilment of such conditions involved, as a little reflection will show, a great deal more than a mere mechanical rotation of employment; for the problem was, always to have available an adequate supply of sufficiently rested troops for a prospective demand which, although varying always in accordance with the changing situation, had nevertheless to be predicted or conjectured.
August 21st found our front line much about the same as that of August 13th, although generally more advanced and straightened out. The Corps frontage was still over 16,000 yards, and upon the completion of the series of reliefs to which I have alluded the dispositions of the Corps were as follows: The Fourth Australian Division from Lihons to just south of Herleville, the 32nd British Division opposite Herleville, the Fifth Australian Division in front of Proyart, and the Third Australian Division on the north of the river. The First and Second Divisions were in Corps Reserve, the former having by then had a good rest from its Lihons fighting. The Liaison Force had been broken up; and the 32nd British Division (Major-General T. S. Lambert) had joined my command in substitution for the 17th Division, which had been withdrawn to join the Third Army.
Such was the situation of the Australian Corps, when on August 21st the short period of comparative inactivity came to a close, and it was destined soon to go forward to further decisive events. On the previous day the French opened a great attack in the south, which yielded 10,000 prisoners on the first day, and on the day in question the Third British Army delivered north of Albert the attack which had been expected for some days. Thus the enemy would have his hands full in endeavouring to parry those fresh blows; and the time seemed appropriate for another stroke on the front of the Fourth Army.