The Russian mobilization was swifter than envisaged by German plans, aided by the fact that two fifths of the Russian army were already stationed in the west before the war started, and both I and II Russian armies were ready for deployment by mid August 1914. On paper the Russian forces, at 208 infantry battalions and 228 cavalry squadrons, facing just 100 battalions of the German VIII army in East Prussia, were well placed to attack westward as envisaged by the Russian “Plan 19”. Early indications were that the Russians would do well and first contact,in the Gumbinen area was a victory for the Russians. Prittwitz, the commander of VIII army lost his nerve and planned a withdrawal. He was sacked and replaced by Hindenberg and his chief of staff, Ludendorf.
On the 27th of August confused contact between Samsonov’s II army and the Germans led to the Russians completely misreading the tactical situation and blundering forward and opening a flank to encircling German forces led by two of the German’s most able commanders, Francois and Mackenson. By the 28th Russian withdrawal was impossible. II army was destroyed and over 100,000 Russian prisoners were taken and only a 10,000 escaped to withdraw across the border . Samsonov alone in the woods,shot himself,
Ludendorf then turned his attention to Rennenkamp’s I army and in the battle of the Masurian lakes confused fighting led to a German tactical success with 30,000 Russians taken prisoner and the successful withdrawal of the I army back across the border.
Ludendorf would laud these actions as great strategic successes but the reality was that German staffing and command and control told against Russian inactivity and poor leadership, and the victories were only tactical. The Russians would soon launch new attacks on East Prussia. What was shown was that frontal attacks were inevitably costly failures and circling flank attacks would set the pattern for fighting for 1914 and 1915. Unlike the Western front the Eastern front, as in the Second World War, would be dominated by the vast open space of Eastern Europe. Trenches would be few and the war would remain one of maneuver
Ludendorf wanted to show the Eastern front as a decisive area of action to counter the view of Falkenheyn that the war could only be won once the British army in Flanders, on the Western front, was destroyed. (This view was mirrored by Douglas Haig who argued, correctly, that only the defeat of the German army in Flanders could end the war).