Battle of Tannenberg

The Battle of Tannenberg, also known as the Second Battle of Tannenberg, was fought between Russia and Germany between 26 and 30 August 1914, the first month of World War I. The battle resulted in the encirclement and the almost complete destruction of the Russian 2nd Army by the German 8th Army and the suicide of its commanding general, Alexander Samsonov. A series of follow-up battles (First Masurian Lakes) led to the ousting of the Russian 1st Army from East Prussia.

The outcome brought considerable prestige to the German army commander, General (later Field Marshal) Paul von Hindenburg, and his rising staff-officer Erich Ludendorff. Although the battle actually took place near Allenstein (Olsztyn), Hindenburg named it after Tannenberg, 30 km (19 mi) to the west, in order to avenge the Teutonic Knights' defeat at the First Battle of Tannenberg 500 years earlier.

The East Prussian campaign is particularly notable for fast rail movements by the German 8th Army, enabling them to concentrate against each of the two Russian armies in turn, first delaying the 1st Army and then destroying the 2nd before once again turning on the 1st days later. It is also notable for the failure of the Russians to encode their radio messages, broadcasting their daily marching orders in the clear, which allowed the Germans to make their movements with the confidence they would not be flanked. After the battles of Stallupönen and Gumbinnen, the German army was forced to retreat by the 1st Army. Yakov Zhilinsky, the leader of the Russian Northwestern Front, of which the 2nd and 1st Armies were a part, based on a report from the 1st Army, drew a non-existent picture for Samsonov about the German withdrawal, partly to the Vistula, partly to Königsberg, without any knowledge of the order in which they were withdrawing or where they were located. Samsonov's Russians, in turn, uncertain of the German army's exact location, acted as if counting "on a miracle" during their offensive.

In the course of the Russian offensive into East Prussia, there was no agreement between Samsonov and Zhilinsky, concerning the direction in which the 2nd Army would engage in battle; Samsonov moved to the northwest ("Allenstein – Osterode") and intended to continue, but Zhilinsky intended to strike north ("Seeburg – Allenstein"). This disorganized leadership contributed to the disastrous defeat as well; it was globally present in the senior command staff. In the end of disputes about the army's movement, Zhilinsky chose to find the golden mean, – he gave in to Samsonov, with the fact that the latter agreed to detach only the 6th Army Corps to Bischofsburg, in the direction that Zhilinsky intended. This corps escaped encirclement, though it was also defeated separately. Zhilinsky did not give Samsonov any specific orders at Tannenberg; the latter actually acted independently and this already put pressure on the psyche of Samsonov. In addition to the previous, the Imperial Russian Army began the war without a sufficiently trained officer corps, with a small reserve for new formations and for the training of conscripts, with a sharp, compared to the Germans, shortage of artillery, very poorly supplied with all technical means and ammunition, having in its rear a country and its military administration unprepared for waging a major war and an industry completely unprepared for the transition to work for military needs. Moreover, the Russians also had problems supplying their armies due to bad local infrastructure and with the fact that they deployed very significant horsepower (cavalry), which required larger food supplies that were already critical.