Tannenberg, battle of (1914). The first major encounter between the German and the Russian empires in WW I ended in a major tactical victory for the Germans whose mythic significance (revenge for the destruction of the Teutonic Knights in 1410) was arguably greater than its military importance. The Schlieffen Plan allowed only token forces to be left for the defence of East Prussia against a Russian army whose significant improvement since the Russo-Japanese war encouraged the belief that it could defeat Germany and Austria-Hungary simultaneously instead of concentrating against one at a time. On the outbreak of war the Russian First Army advanced west from the Nieman river; the Second moved north-west from the Narew. Co-ordination between them was poor, due to inadequate communications, bad staff work, and the geographic barrier of the Masurian Lakes. Nevertheless the Russian plan of using their significantly superior numbers to encircle the German Eighth Army had good prospects of success, especially when German commanders panicked after being defeated by the First Army at Gumbinnen on 20 August. The First Army, however, failed to follow up its victory while poor logistics and worse intelligence handicapped the Second's advance. As a result the Eighth Army's new command team of Hindenburg and Ludendorff was able to implement plans, already outlined by the Eighth Army's staff officers, to concentrate their entire force against the Russians coming from the south.
The German railway network merits the credit it received for its rapid movement of men and supplies between the theatre's two sectors. A bit of insubordination was involved as well. The commander of the German I Corps refused to attack until his artillery arrived, a delay that gave the Russians two more days to push forward into a tightening German noose. On 27 August I Corps crushed the Second Army's left wing. Two more corps, who had reached their position by hard marches in the August heat, drove in the Russian right. The Second Army's commander saw neither of these local defeats as decisive and sought to master the situation by driving forward with the five divisions of his centre. The Russians came closer to success than is generally realized, but proved unable to break through their opponents. By the evening of 28 August, German forces advancing on the flanks had closed a circle around Second Army. The final balance sheet showed 50, 000 Russians dead or wounded and another 90, 000 POWs.
The adversaries in the Tannenberg campaign were reasonably well matched. The Russian failure was less a consequence of general institutional incompetence than of an attempt to employ a concept of manoeuvre warfare their field forces could not execute. While Russian losses in men, material, and morale were severe, the battle had negative consequences for the Germans as well. It established a model of decisive victory that discouraged realistic assessment of what could be achieved by military means under the conditions of 1914-18.
— D. E. Showalter
