During the series of offensive actions known as the Battle of the Somme, the French town of Thiepval has seen new British innovations in trench warfare, including the first tanks and mortar-fired gas shells. Weather has determined the pace of operations here, where the British line faces north towards Thiepval Ridge. Attacking towards those heights, the Reserve Army under Lieutenant-General Sir Hubert Gough has succeeded in whittling German defenses down until only the Schwaben Redoubt remains in their path (see above). By seizing the high ground overlooking the valley of the Ancre river behind it, Field Marshal Douglas Haig hopes to maximize German casualties by meeting counterattacks with massed artillery fire.

It is a busy day in the Somme region. To the south, a French assault on a front over a mile long succeeds in capturing the German first line. The XIV British corps is thrown back, but the South African III Corps and British Army units score tactical victories around the bulge that has formed in the line since June 1st. Today’s main event, however, is the 39th Division’s reckoning with the Schwaben Redoubt, which recently managed to hold out against the previous unit here, the 18th Division, for eight days.

A fortress guarded by three heavy and four light machine gun emplacements, the Schwaben Redoubt is bigger than meets the eye, for most of it lies underground, carved out of the chalky soil. A labyrinth of tunnels connects the open trenches to bunkers, medical facilities, and even a telephone switchboard — all manned by troops of the 28th Reserve Division in the German 1st Army. Attacked no less than six times between July and the end of September, it has briefly fallen once only to be lost to an immediate counterattack, inflicting heavy British casualties throughout.

Australians in dugouts at Thiepval. Cut into the side of the trench facing the enemy, they offered little protection

Going over the top at 2:45 PM, the men of the Cambridgeshire Regiment, known as “The Territorial Fen Tigers,” advance behind a creeping barrage. Since June, British artillery officers have gotten measurably better at this tactic, which sounds much simpler than it has turned out to be in execution, for the safety margin between the advancing infantry and their protective curtain of fire is always large enough for the enemy to pop back out of his hideaways and rake the ground with machine guns. This time, aircraft buzz overhead the whole day, directing the barrage with precision and putting counterbattery fire on pre-registered target areas where they observe enemy guns firing. These tactics succeed in suppressing the German artillery and giving the Tigers every last possible moment of protection.

Lt Col Edward Riddell’s men have practiced and prepared for the advance — cutting their ways through the wire, using mortars and machine guns to to pin the enemy down, and surprising the Germans with the speed of their assault. For the next seven hours, the Cambridgeshire men fight a brutal close-range battle characterized by pistols, bayonets, and grenades. The unit entirely consumes its very large supply of hand bombs clearing one defensive position at a time until the remaining defenders surrender before midnight. Rather than hunker in the captured fortress, however, the victorious British soldiers advance another 100 yards up the slope and dig a hasty new trench connecting a row of shell holes, completing the arrangement with their own supply of barbed wire.

This turns out to be the decisive element of the engagement, for when the German counterattack begins at 4 AM, the Cambridgeshire men are not in the captured position as it comes under heavy bombardment. The assaulting infantry approaches in the dark without knowing the wire defenses are in place, or defended by a forward sap, and the result is a slaughter. Rifle and light machine gun fire stop the German wave cold on the hasty wire. Dawn breaks to find the chalk fortress still in allied hands, and after after 24 hours the Cambridgeshire ‘Tigers’ are relieved of duty.

They have lost 32 dead and 186 wounded — a mere drop in the river of blood that flows on the Somme this year.

As hoped, General Fritz von Below reacts by ordering more counterattacks to regain the lost position, reinforcing the failure of his line. Fighting from the advantage of a reverse-slope, the British Reserve Army (which becomes Fifth Army at the end of the month) is difficult for his artillery to target and well-positioned to inflict horrendous losses on infantry formations as they top the ridge. All of these operations fail, consuming much-needed reserve troops for no gain until French actions at Verdun force an end to them.

In that sense, the end of the Battle of the Ancre Heights is a complete success for Haig’s operational strategy and the emerging doctrine of combined arms. We are not used to thinking of 1916 in this light, but if only every day could go this well, then the war might be over by January. The mere act of achieving brilliant tactical success through combined arms like this demands the coordinated action of hundreds or thousands of specialized teams using specialized machinery and equipment to deliver a mountain of ammunition at exactly the right place and time. That is hard to do. It can be undone by a rainstorm, and even the best-laid plans must alter upon enemy contact because battle is chaos.

Seldom do plans go this well; even more rare is ground so favorable for the attacker to take and hold.

An overhead photo of the Schwaben Redoubt. Note the two forward saps at bottom left pointing toward the British line