Battle of the Sambre
The Battle of the Sambre was the last large-scale set-piece battle of the Great War. The German army was determined to hold a defensive line incorporating the Mormal Forest and the Sambre-Oise canal, hoping to buy time for a strategic withdrawal to the Meuse and thereby negotiate a compromise peace. The first barrier to the northern attack was the 60–70-foot (18–21 m)-wide Sambre Canal and the flooded ground around it. It was there that the BEF had fought over four years earlier. The XIII and IX Corps reached the canal first. German guns quickly ranged the attackers, and bodies piled up before the temporary bridges were properly emplaced under heavy fire.

The 1st and 32nd Divisions of IX Corps lost around 1,150 men in the crossing, including celebrated war poet Wilfred Owen. Even after the crossing the German forces defended in depth amid the small villages and fields, and it was not until midday that a 2-mile-deep (3 km) by 15-mile-wide (24 km) breach was secured. Lieutenant Colonel D.G. Johnson was awarded the Victoria Cross for leading the 2nd Battalion Sussex Regiment's crossing of the canal. Further north, IV and V Corps attacked into Forêt de Mormal. At Le Quesnoy, the Germans defence was haphazard: the 13th Royal Welsh Fusiliers hardly needed to use their guns, while the 9th Battalion of the 17th Division lost all but two officers and 226 of 583 soldiers. Despite this, the advance continued and the battle objectives were reached on the 4th or the following day. To the south, the French First Army attacked, capturing the communes of Guise (the Second Battle of Guise) and Origny-en-Thiérache (the Battle of Thiérache). This resulted in a bridgehead almost 50 miles (80 km) long being made, to a depth of 2–3 miles (3–5 km). From this point, the northern Allies advanced relentlessly, sometimes more than five miles a day, until the Armistice Line of 11 November from Ghent, through Hourain, Bauffe, Havré, to near Consoire, and Sivry.