The Race to the Sea developed out of the first battle of the Aisne (13-28 September 1914). This saw the Germans retreat from the line of the Marne to the line of the Aisne, which would become their front line until 1918. The battle of the Aisne began with a series of attempts to break through the German lines. When these attacks failed, Joffre and Falkenhayn both began to plan to turn each other's northern flank.
Joffre made the first move, using Maunoury’s Sixth Army in an advance up the Oise, at the western end of the Aisne battlefield. Joffre ordered Maunoury to advance on the right bank of the river, giving him more space to move around the German flank (Kluck’s First Army). Instead, the French Sixth Army moved up the left bank, nearer the Germans, and did not cross over to the north until 17 September. By that point Kluck had already moved his own right wing across the river, and the French advance stalled.
Having attempted to turn each others flanks with troops already on the Aisne, both Joffre and Falkenhayn now brought in new armies from Lorraine. The French Second Army (Castelnau) formed up south of Amiens, the German Sixth (Crown Prince Rupprecht) around St. Quentin. The Germans also used their Seventh Army (Heeringhen), which had earlier been used to plug a gap on the Aisne.
Castelnau began to advance on 22 September, with support from the Sixth Army from 23 September (first battle of Picardy, 22-26 September). On 24 September a full scale battle developed along the entire line from the Oise to the Somme. The Germans concentrated their attack at Roye, half way between the two rivers, hoping to cut off the French armies advancing to the north. Their attack failed, but did force Castelnau to abandon his offensive plans.
The fighting now began to move north of the Somme. On 25 September the Germans attacked Albert, just north of the river (battle of Albert, 25-29 September), but were held off by Castelnau’s Second Army. At the same time both sides continued to move north.
The focus of the fighting now reached Arras (first battle of Artois, 27 September-10 October). There two corps from Castelnau’s army, under the command of Maud’huy, were advancing north east along the Scarpe, towards Vimy. Their southern flank was guarded by a thin line of territorials. On 28 September Prince Rupprecht was ordered to attack Arras. He planned to pin Maud’huy in place, and then outflank him to the north. His plan came close to success.
By the end of 4 October German troops were north and south of Arras and Maud’huy was beginning to plan for a retreat. Joffre responded by reorganising the northern armies. Maud’huy’s command was split from the Second Army, and became a new Tenth Army. Both Maud’huy and Castelnau were firmly ordered not to retreat. Finally, Foch was appointed to overall command of the northern armies, including both the Second and Tenth. Foch was able to reinvigorate the French and Allied commanders in the north,
The focus of attention now swung even further north, to Flanders. The BEF began to arrive at Abbeville by train on 8-9 October, and at St. Omer on 10 October. Further north IV corps had been shipped to Ostend and Zeebrugge, to either help defend Antwerp or to help the Belgian army retreat. It was hoped that the British would be able to advance north east of Lille and outflank the German Sixth Army, fighting around Arras. Instead the advancing British ran into another new German army, the Fourth, under the Duke of Württemberg. The result was a series of encounter battles, beginning at Le Bassée on 10 October and continuing north to Messines (12 October) and Armentieres (13 October). Meanwhile the Belgian army had left Antwerp and was heading west towards the Yser, while the British IV Corps was heading towards Ypres from the east.
On 14 October the Race to the Sea effectively ended when the British Cavalry Corps, advancing from the west, met the 3rd Cavalry Division, moving south west around Ypres. There was now a continuous allied from the North Sea to the Swiss border. On 18 October fighting began on the Yser (18 October-30 November). The British continued to believe that there was a gap in the German line, this time around Ypres, and began to plan for another advance. Instead, on 19 October the British and French troops around Ypres came under German attack. The first battle of Ypres was underway.
The Race to the Sea now became the Battle of Flanders. The Germans made repeated attempts to break through the new Allied line, without success. The line of the Western Front would remain almost entirely static for the next two years, only changing in early 1917 when the Germans voluntarily withdrew from the Somme battlefield to the Hindenburg Line. The period of mobile warfare was over, and the period of trench warfare had begun.
The Race to the Sea is perhaps not the best name for this series of events. It implied that the troops involved all came from the Aisne, and were dashing north to extend the line. This was not true on either side. Some of the troops involved had been transferred Lorraine, while others were coming in from Antwerp (Belgian and German) or from the channel coast (British and French). New troops were thrown into the fight as quickly as they became available. The name also implies that one or the other side wanted to reach the coast. When the race began neither side wanted it to end on the coast. Both sides were aimed to get around their opponents exposed northern flank, the Germans with the hope of winning the decisive final battle, or at least of capturing all of the channel ports, the French in the hope of getting behind the German armies that had advanced to the Marne. The Race to the Sea ended in a failure for both side.