[10] Hindenburg issued new tactical instructions in Grundsätze für die Führung in der Abwehrschlacht im Stellungskrieg ("Principles of Command for Defensive Battles in Positional Warfare") which ended the emphasis on holding ground at all costs and counter-attacking every penetration.

Manpower was to be replaced by machine-generated firepower, using equipment built in a competitive mobilisation of domestic industry under the Hindenburg Programme, the policy rejected by Falkenhayn as futile, given the superior resources of the coalition fighting the Central Powers.

Ludendorff also ordered the building of the Siegfriedstellung, a new defensive system 15–20 mi (24–32 km) behind the Noyon Salient (which became known as the Hindenburg Line) to make possible a withdrawal while denying the Franco-British the chance to fight a mobile battle.

By 1908, the British army had adopted vehicles with caterpillar tracks to move heavy artillery and in France, Major Ernest Swinton, (Royal Engineers) heard of the cross-country, caterpillar-tracked Holt tractor in June 1914.

In October, Swinton thought of a machine-gun destroyer that could cross barbed wire and trenches and discussed it at GHQ with Major-General George Fowke, the army chief engineer, who passed this on to Lieutenant-Colonel Maurice Hankey, the Secretary of the War Council.

Swinton persuaded the War Office to set up an informal committee which in February 1915 watched a demonstration of a Holt tractor pulling a weight of 5,000 lb (2,300 kg) over trenches and barbed wire, the performance of which was judged unsatisfactory.

Churchill set up a Landships Committee, chaired by Eustace Tennyson d'Eyncourt, the Director of Naval Construction, to oversee the creation of an armoured vehicle to crush wire and cross trenches.

[18] In March 1916, Swinton was given command of the new Heavy Section, Machine-Gun Corps, raised with manpower from the Motor Machine Gun Training Centre at Bisley, with an establishment of six companies with 25 tanks each, crewed by 28 officers and 255 men.

Female tanks were similar in size, weight, speed and crew and were intended to defend the males against an infantry rush, with their armament of four Vickers machine guns, a Hotchkiss machine-gun and a much larger allotment of ammunition.

A second line of defence ran from Chaulnes (behind woods to the west and north and the château park, from which the Germans had observation over the ground south of the Flaucourt plateau), Pressoir, Ablaincourt, Mazancourt and Villers-Carbonnel.

The attack took place from Chilly north to Barleux, intended to gain ground on the Santerre plateau, ready to exploit a possible German collapse and then to capture crossings over the Somme south of Péronne.

Control of the creeping barrage was delegated to commanders closer to the battle and a communications system using flares, Roman candles, flags and panels, telephones, optical signals, pigeons and message runners was set up to maintain contact with the front line.

Transport difficulties became so bad that General Adolphe Guillaumat, the I Corps commander, ordered all stranded vehicles to be thrown off the roads and supply to continue in daylight, despite German artillery-fire, ready for the resumption of the attack on 12 September.

The Germans tried to resort to occasional methodical counter-attacks (Gegenangriffe) on a broad front, to recapture tactically valuable areas but most of these failed too, because of insufficient men, artillery and ammunition.

Prisoners taken near Bouleaux Wood said that Spitzgeschoß mit Kern (S.m.K., bullet with core) ammunition had been issued and that grinding noises had been heard from behind the British lines, which was taken to be mining but the "sinister, noisy sounds" had stopped during the night of 14/15 September.

The II Corps on the left flank was to exploit chances to take ground, especially to the south of Thiepval, where cloud gas was to be released and the 49th Division was to simulate an attack with a smoke screen.

Two cavalry divisions were swiftly to pass between Morval and Gueudecourt and after an all-arms force had established a defensive flank from Sailly-Saillisel to Bapaume, the rest of the Fourth Army could attack northwards and roll up the German defences.

An exploitation force like that of 1 July was not assembled but the Cavalry Corps objective was high ground between Rocquigny and Bapaume and the German artillery areas from Le Sars to Warlencourt and Thilloy.

German artillery-fire in the area was extensive and counter-attacks at Cléry during the night of 19/20 September, at Le Priez Farm and Rancourt during the morning and at Bouchavesnes later, were repulsed by the French only after "desperate" fighting.

Attempts to sort out the units were made and it was thought that the third objective, 1,300 yd (1,200 m) on had been reached; a messenger pigeon was sent back, despite a Forward Artillery Observer (FOO) realising the mistake.

XIV Corps HQ found that the mist and smoke had stopped contact patrol aircraft from watching the attack; the German artillery reply cut telephone lines and caused long delays in the arrival of runners.

Returning wounded alerted BIR 5 in Flers Riegel who fired red SOS flares, sent messenger pigeons and runners to call for artillery support but none got through the bombardment being maintained on the Bavarian rear defences.

The 6th Canadian Brigade made slower progress against Reserve Infantry Regiment 210 but reached the objective around 7:30 a.m., the left-hand battalion over-running a strong point on the Ovillers–Courcelette track and up McDonnell Trench, from where machine-guns could be fired eastwards along the new front line.

Pioneers behind the Canadian lines dug several communication trenches forward despite German shell fire and engineers worked on tracks and strong points, the sugar factory being fortified and provided with water from a repaired well.

[76][e] The attack at Flers was watched by 3 Squadron and the first report was dropped at the XV Corps HQ at 7:20 a.m., that the infantry had followed a highly accurate creeping barrage as a stream of emergency rockets were fired from the German trenches.

[84] In 2003, Sheffield wrote that the verdict of Wilfrid Miles, the official historian, was accurate, the Germans "...had been dealt a severe blow" but the attack "fell far short of the desired achievement".

[90] In his 1963 biography of Haig, John Terraine wrote that after the war, Churchill held that the prospect of a great victory by using tanks en masse had been squandered by their premature use to capture "a few ruined villages".

Nerve shattering!Die Fliegertruppen on the Somme had received LFG Roland D.I and Halberstadt D.II fighters early the battle, which were faster and better armed than the obsolete Fokker E.III and inflicted losses on the RFC squadrons equipped with the most inferior aircraft.

[104] After the defeat in September, Hindenburg and Ludendorff sacked the 2nd Army Chief of Staff, Colonel Bronsart von Schellendorf and ordered more counter-attacks, a predictable tactic by that period and these Gegenangriffe were easily repulsed by French and British artillery and small-arms fire.

[113] The 41st Division erected a memorial in Flers, commemorating the capture of the village; topped with a bronze battle dressed soldier, the statue is well known as the photograph on the battlefield tour guide Before Endeavours Fade (Rose Coombs).