Rawlinson) had pushed the Germans back a considerable distance; units were feeling the strain badly, and fresh troops were needed.
On 9th September a successful attack had given us Ginchy and Leuze Wood, but the Germans were holding very strongly the high ground which lies in the form of a horseshoe between the above-named points, and which dominates the country for some distance to the south.

The trenches followed the shape of the spur roughly at the back end of the horseshoe, and covered access was given to them by a sunken road leading back to the deep valley which runs north from Combles.
At the top of the spur, just south of the railway and communicating with the sunken road, was a four-sided trench in the form of a parallelogram of some 300 yards by 150 yards, called by us the Quadrilateral.
It was this strong point and the adjoining trenches which had held up the advance of the Fourth Army on the 9th September, and it was the first task of the 6th Division to obliterate the horseshoe and straighten the line preparatory to a general attack on the 15th September.
On 12th September attacks by the 56th Division on the south and the Guards on the north reduced the neck of the horseshoe, or pocket, to about 500 yards, but could not close it.

The situation within the horseshoe was undefined, and the exact positions of the Quadrilateral and other trenches were not known, owing to the bad flying weather.
Even our own positions were in doubt, as almost every vestige of roads, railways and even villages had disappeared under the continuous bombardments.
On night 11/12th September the 71st Infantry Brigade (Brig.-Gen.

J.F.
Edwards) relieved part of the Guards Division and the 16th Infantry Brigade (Brig.-Gen.

W.L.Osborn), part of the 56th Division, with orders on the 13th September to straighten the line by capturing the Quadrilateral.