[b] On the left of XII Corps to the east of the Suippes river, the 24th Division established a flank guard by attacking through Bois des Abattis towards Germains and Baden-Baden trenches.

The loss of Fort Brimont would make the German positions on the low ground south of the Aisne, from Berméricourt north-west to the mouth of the Suippes, vulnerable to another attack.

Success would allow the Fourth Army to advance towards the Suippes, between St Martin l'Heureux and Warmeriville to the north-west, outflank the Nogent l'Abbesse hills from the north.

Villages, woods, roads, railway lines, cantonments, bivouacs, artillery batteries and ammunition dumps were "deluged" by shellfire, with few pauses until dawn on 17 April.

Poor weather interfered with air-observation but by the night of 16 April, reconnaissance photographs taken from the air, reports from ground observers and prisoner reports, showed that wide lanes had been cut through the barbed wire entanglements in front of the German first line, where they had not been obliterated and that German trench lines and field fortifications, particularly south of Mont Sans Nom had been destroyed.

[9] The Fourth Army plan was to capture Bois de la Grille, Leopoldshöhe Trench and all of the south face of the Moronvilliers hills, push the Germans back from Le Golfe and encircle Aubérive from the flanks.

If Le Téton had not been captured, the troops in the French centre, were to drive the Germans from Bois de Côte 144 and attack the hill from the east.

East of the Suippes, on the right flank of the XVII Corps, four and a half battalions were to attack Aubérive and the trenches beyond, up to those at the western fringe of Bois des Abatis.

The hills on the edge of the Châlons plain could be outflanked from west to east, only after the German defences on either side of the Thuizy–Nauroy road and between Mont Sans Nom and the Suippes had been captured.

The main German defensive position was in the ruins of Bois de la Grille to the south-west of Mont Cornillet and west of the Thuizy–Nauroy road.

An attack from the east on the hills was blocked by the entrenchments from Mont Sans Nom to the Suippes, which ran south-east around Aubérive-sur-Suippes on the left bank of the river.

Higher up the slope, another trench led to Grand Bois de la Côte 179 and protected Le Téton from an attack from the north-east.

An advance down the right bank of the Suippes, towards Dontrien and St Martin-l'Heureux and the Bazancourt to Somme-Py and Apremont railway, was obstructed by a trench system east of Aubérive and Bois de la Côte 152.

A second line higher up the ridge, was joined to the first by the Leopoldshöhe Trench, a fortified approach from the north of Bois de la Grille to the Thuizy–Nauroy road.

The 20th Regiment captured redoubts around Bois du Chien, after fighting all day and then began preparing a dawn attack Le Casque.

[21] Field artillery moved forward and engaged the Konstanzlager from near Bois-en-Escalier but the reinforced concrete structure was so resilient, that the attack on the redoubt and dug-outs was postponed, until a bombardment by heavy howitzers could be arranged next day.

At 5:45 a.m., the French took the east end of Erfurt Trench, despite delays as some redoubts held out, reached the edge of Bois de Mont Perthois by noon and then repulsed four German counter-attacks before nightfall.

[22] In the VIII Corps area, the 34th Division east of the Thuizy–Nauroy road, attacked at 4.45 a.m., with two regiments and an hour later, could be seen threading their way up the heights, bombing dug-outs and fighting hand-to-hand in the open with German infantry.

[24] The 2nd Battalion of the 83rd Regiment, held on to the north end of the trench until 5:30 p.m., when it ran out of ammunition and withdrew behind the crest, where the survivors repulsed a German attack at midnight.

[24] The 16th Division (General Le Gallais), attacked on the extreme left flank, west of the Thuizy–Nauroy road against Bois de la Grille and Leopoldshöhe Trench.

The two regiments in the centre and on the right were stopped by the German machine-gun fire from Wahn Trench, which ran from the Thuizy–Nauroy road, through the south end of Bois de la Grille.

West of the Thuizy–Nauroy road, the French artillery bombardment failed to destroy many of the German fortifications and some of the trees in Bois de la Grille were still standing.

[19] In the XVII Corps zone, the 45th Division attacked, after a "devastating" howitzer bombardment at 7:00 a.m. on the Konstanzlager and the dug-outs nearby and after thirty minutes, the garrisons surrendered.

[19] In the XVII Corps area, part of Fosse Froide Trench was captured by the 45th Division, which endangered the communications of the German garrison on Mont Perthois.

German reinforcements were assembled in echelon from Mont Haut westwards to Nauroy and attacked all day, until a final effort failed at 4:00 p.m.[24] In the XVII Corps area, the French captured Bois Noir.

French heavy artillery-fire blocked some tunnels, subways, deep dugouts and caverns, entombing German troops and others were overrun and captured.

The French gained the crest after a costly advance and broke up into groups, which bombed and bayonetted their way through the German shell-hole positions and pillboxes, against enfilade fire from machine-guns in Flensburg Trench and the west slopes of Mont Blond.

[33] An Engineer company followed close behind the infantry, ready to block the tunnel entrances but found them difficult to find, because the bombardment had covered them up.

At dusk, the French consolidated the craters on the northern crest; near midnight some German soldiers were captured as they headed for Nauroy, who turned out to be from the tunnel garrison and disclosed the main entrance.

German counter-attacks had mostly been costly failures and from 16 April to 2 June, the Franco-British had taken c. 52,000 prisoners, 440 heavy and field guns, many trench mortars and more than 1,000 machine-guns.