At dawn, on August 21, the 4th and 6th Corps of Byng's Army attacked between Miraumont and Moyenneville.
Supported by tanks, they captured the advance defences in brilliant style.
The fighting was particularly severe around Achiet-le-Grand and Logeast Wood, where, however, the advance continued steadily. The Arras-Albert railway which was the enemy's principal line of defence, was reached, 2,000 prisoners being taken.
After this preparatory attack, the offensive was launched on August 22, along a thirty-two mile front, between Lihons and Mercatel.
South of the Somme, the Australians captured Herleville and Chuignes, with 2,000 prisoners. Rawlinson's left crossed the Ancre, took Albert, and advanced its front to the hills east of the Albert-Braye road, capturing 2,400 prisoners.
But the hardest blow was struck further north by Byng's Army. Advancing beyond the principal line of defence (the Arras-Albert railway), the 4th and 6th Corps took Gomiécourt, Ervillers, Boyelles, many guns, and more than 5,000 prisoners, then pushed on towards Bapaume and Croisilles. The 6th Corps, astride the Arras-Bapaume road, marched on Bapaume, threatening to cut off the Germans who were hanging on to the Heights of Thiepval. The latter, attacked at the same time further south, fell. Bray-sur-Somme was also captured.
The battle continued from the 25th to the 29th, the enemy's resistance stiffening steadily.
Counter-attacking, the Germans defended this old battlefield of 1916, strewn with obstacles, with great desperation.
On the 29th, Bapaume fell, and the Germans retreated from the north of that town to the Somme, on the line Cléry, Combles, Frémicourt, Bullecourt, and Heudecourt.