First Battle of the Aisne

Background

On 5–12 September 1914 the Allies had turned the German right wing at the Marne. The German First and Second Armies, at risk of encirclement, fell back about 65 km to high ground north of the Aisne, while Moltke visited the other armies on 11 September and ordered them to retreat as well. On 10 September Joffre had ordered the French armies and the British Expeditionary Force to advance; for four days the left-flank armies met only rearguards, capturing stragglers, wounded men and equipment. The pursuit was slow, averaging about 19 km a day, because the troops were exhausted, and attempts to outflank the Germans on 11–12 September were too slow to catch them.

The Aisne was the first real obstacle. The river runs in a valley with a canal beside it, and the northern bank rises to a plateau along the Chemin des Dames ridge. The Germans turned to face their pursuers on 13 September and held the higher ground beyond the crest; the Chivres–Val escarpment was the strongest point on their line. Falkenhayn replaced Moltke as chief of the German General Staff on 14 September, and Bülow was given temporary command of the First, Second and Seventh Armies for the attacks of 15–19 September. What had begun as a pursuit became a battle that nobody on either side could finish, and the front it created lasted, with changes, for years.

The armies

The Allied side was Joffre's French Fifth, Sixth and, in the wider fighting, Ninth, Fourth and Third Armies, with the British Expeditionary Force on the line between the Fifth and Sixth Armies. The BEF's order of battle on the Aisne was Gough's cavalry division (3rd and 5th Cavalry Brigades), I Corps under Haig (1st and 2nd Divisions), II Corps under Smith-Dorrien (3rd and 5th Divisions) and III Corps under Pulteney (4th Division and the 19th Infantry Brigade). Maunoury commanded the French Sixth Army and Franchet d'Espèrey the Fifth.

The Germans fought with the First (Kluck), Second (Bülow) and Seventh (Heeringen) Armies, reinforced as the battle went on. The IX Reserve Corps arrived from Belgium by 15 September, while the French moved the XIII and IV Corps and the Second Army across from the eastern front.

No source I could reach gives reliable strengths for the Aisne alone. For the Marne, a few days earlier, Herwig gives about 980,000 French and 100,000 British soldiers between Paris and Verdun against about 750,000 Germans, and says the German First and Second Armies had fallen from 580,000 in August to 372,000. Those are not Aisne figures. CDB90's totals are given in the fact sheet. What decided the battle was less numbers than ground: defenders on the plateau with observation over the river and the crossings, against attackers on the lower slopes, short of entrenching tools and heavy guns.

The battle

Crossing the river, 13 September. In dense fog on the night and morning of the 13th, most of the BEF crossed on pontoons or partly demolished bridges, at Bourg-et-Comin on the right and Venizel on the left. On the French side the Fifth Army crossed at Berry-au-Bac and took the eastern tip of the Chemin des Dames. Contact was made along the whole front, with lead elements reaching the lower slopes below the Germans, who were digging in along the ridge. This is CDB90's engagement 277, which it dates 13–19 September.

The plateau, 13–14 September. When the mist lifted, British troops on the paths up to the plateau came under flanking fire. Bridges were damaged and the 1st Division's move was delayed; it crossed under shellfire, lined a ridge north of Bourg and billeted in the village. East of the Chemin des Dames the French Fourth, Fifth and Ninth Armies made negligible progress. On 14 September Sir John French ordered the BEF to entrench, with too few tools; shallow pits were later deepened to about seven feet.

Frontal attacks, 15–16 September. Falkenhayn ordered the First Army to fall back and dig in on 15 September, but the order was soon cancelled. The German IX Reserve Corps was to attack with the First Army, but the attack was also cancelled and the corps withdrew. French attacks by the Fifth, Ninth and Sixth Armies on 15–16 September had little success. On the 16th the 3rd Infantry Brigade, including the 1st South Wales Borderers, supported the 2nd Brigade near Moulins and attacked a high ridge to the west in about eight hours of fighting, ending near Troyon.

Joffre's western shift, 17–19 September. On 17 September the French Sixth Army attacked from Soissons towards Noyon and reached Carlepont and Noyon before being contained on 18 September. Joffre then moved the Second Army west to the Sixth Army's left, which began the sequence of attempts to outflank each other that became the Race to the Sea.

Stalemate, 20–28 September. The BEF fought on at the Aisne heights on 20 September and at Chivy on 26 September, where at 4.15 am the Germans attacked the 1st South Wales Borderers on the left of the line; a quarry was briefly lost and retaken, and the fighting eased by about 3 pm. On 24 September two British officers spotted three concealed German batteries from the air and relayed their positions, and on 27 September German rifle grenades were first used against British troops. The Aisne front had stabilised by 28 September, and the BEF began to pull out on the night of 1–2 October to go to Flanders.

Aftermath

Nobody has a reliable casualty count for the whole battle. The infobox on Wikipedia gives 13,541 British killed or wounded and no figure for the French or Germans; a popular history puts British losses at about 12,000, and another web account says about 5,000 for the BEF, with I Corps losing about 3,500 on 13–15 September. The French official history gives 213,444 French casualties for all of September 1914 on the whole front, and these returns were incomplete. See the flags: I have left the casualty headlines empty rather than guess.

The strategic result was a stalemate. Both sides spent about three weeks trying to turn the other's northern flank, which produced a trench system more than 400 miles long, from Nieuwpoort to the Swiss border. On 29 September Beseler's six divisions attacked the forts at Antwerp, and the Battle of the Yser followed in October. The Aisne is remembered in British accounts as the start of trench warfare for the BEF. Many of the dead are in Vailly British Cemetery. The ridge was fought over again in April–May 1917 and May–June 1918.

CDB90 codes the French and British as attackers and the battle as an attacker loss, which fits a failed attempt to dislodge a dug-in enemy, though the code is not clear-cut.

Wargaming it

The Aisne is a good battle for showing how dramatically ground and entrenchment can beat numbers. At battalion-per-stand or brigade scale you can fit a corps front on a table, with the river, the canal and the steep northern slope as the principal terrain. The Allied player must cross by a handful of bridges and pontoons, which are fragile, often under fire, and have to be fed through in fog that lifts during the first turns. The German player has observation and reverse-slope positions, but the German orders themselves shifted from retreat to hold.

Interesting decisions include whether the British push up the slopes in the fog of 13 September before the Germans are properly dug in, whether to commit the cavalry, and when to give up and entrench. A good design makes entrenching tools and artillery ammunition a scarce resource for the Allies. Aerial observation (the batteries spotted on 24 September) and the first rifle grenades are worth special rules. A larger campaign game can add the French west-flank shift of 17–19 September as the opening of the Race to the Sea. What-ifs: Falkenhayn's cancelled order to fall back, and the IX Reserve Corps attack that was cancelled.

Maps and pictures