On 23 August the 1st Division attacked south of the River Somme towards Chuignes with the British 32nd Division on its southern flank attacking Herleville. The Australians suffered 1,000 casualties but took 2,000 German prisoners out of a total of 8,000 captured by both the British Third and Fourth Armies on that day. The 1st also captured a German 15-in naval gun. On 18 September, despite being severely depleted – only 2,854 infantrymen out of division's 12,204 nominal strength were available – the 1st Division took part in the assault on the Hindenburg "Outpost" Line during the Battle of Épehy, capturing a large section of the line.