After a six-day halt for preparations and artillery bombardments, Fourth Army troops attacked at 5.20 a.m. on Thursday 17 October. On 16 October the US 30th Infantry Division moved up into position between the US 27th Infantry Division and the British IX Corps. Infantry and tanks, preceded by a creeping barrage, the American forces waded across the Selle, moving forward on a front south of Le Cateau (site of the famous
1914 rearguard) with the 27th Division to the north, and the 30th to the south. The Germans had dug in along lines indicated on their maps as Stellung I and II. This combined British Fourth Army forced crossings of the river, despite unexpectedly strong German resistance and much uncut barbed wire. Fighting was particularly fierce along the line of the Le Cateau–
Wassigny railway. The Americans attacked from the center, with the 50th British division to their north, the British 6th Division to the south, made most progress and by nightfall the German defences had been broken and Le Cateau captured. Fighting continued from 18–19 October, by which time Fourth Army, much assisted by the
French First Army on its right, advanced over , harrying the Germans back towards the Sambre–Oise Canal. On the left, First Army advanced forward in the area of the Selle's confluence with the
Escaut/Scheldt. Here, at the northern edge of the attack front, the
Canadian Corps pushed across the
Canal de la Sensée on the 18th and captured
Denain on the 19th, securing the flank for the push across the Selle. The British Third and First Armies, north of the Fourth Army, maintained the offensive pressure the following day. In a surprise joint night attack in the early morning of 20 October, Third Army formations secured the high ground east of the Selle and, further securing the left flank, the Canadians swept around the city of
Valenciennes in the north. Following a two-day pause, to bring up heavy artillery, the attack was renewed on 23 October with a major combined assault by Fourth, Third and First Armies; the fighting, which continued into the next day, resulted in further advances. At this stage, the German Army was retreating at a forced but controlled pace. On 24 October, the German Army
counterattacked at the
Canal de la Dérivation but were repulsed and pushed back by the Belgian Army. ==Aftermath==