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.Showalter, Dennis E. “Tannenberg Revisited: German Operational Success and Russian Failure in 1914.” The Journal of Military History.Alexander Watson – capítulo en The Cambridge History of the First World War, Vol. I (Cambridge University Press, 2013)
The outcome brought considerable prestige to the German army commander, General Paul von Hindenburg, and his rising staff officer, General Erich Ludendorff. Although the battle actually took place near Allenstein (Olsztyn), Hindenburg named it after Tannenberg, to the west, in order to avenge the Teutonic Knights' defeat at the Battle of Grunwald 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.Strachan, Hew. The First World War. Oxford University Press, 2001.
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, present in the senior command staff, contributed to the disastrous defeat as well. In the end of disputes about the army's movement, Zhilinsky chose to find the golden mean, he gave in to Samsonov, on the condition 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 the fact that they deployed very significant horsepower (cavalry), which required larger food supplies that were already critical.Militärgeschichtliches Forschungsamt (MGFA). Das Deutsche Reich und der Erste Weltkrieg, Vol. I–II.
Background Germany entered World War I largely following the Schlieffen Plan. According to Prit Buttar, "In combination with his own strong desire to fight an offensive war featuring outflanking and encircling movements, Schlieffen went on to develop his plan for a sweeping advance through Belgium. In the east, limited German forces would defend against any Russian attack until more forces became available from the west, fresh from victory over the French. The total strength of the fully mobilised German Army in 1914 amounted to 1,191 battalions, the great majority of which would be deployed against France. The 8th Army in East Prussia would go to war with barely 10 per cent of this total."
The Russian Forces were less prepared than they would have otherwise been, thanks to an overestimation of the Russian military and a general who was having real problems on Russia's other fronts. General Yakov Grigoryevich Zhilinsky was in charge of this attack and had pledged to put 800,000 men on the front by the 15th day of mobilization. Due to the rushed nature of this attack, the Russian operation developed numerous cracks and failures as a result of poor communication between the front and command. This lack of communication resulted in orders that would contradict the previous ones and headquarters giving soldiers orders in a hurry. All of this confusion and disorganization severely hampered the general's efforts and progress on the Russian Front stalled.Alexander Watson – “Managing the First Battle of the Marne’s Eastern counterpart: command and control in the Russian invasion of East Prussia, 1914"Bruce W. Menning – Bayonets before Bullets: The Imperial Russian Army, 1861–1914 (Indiana University Press, 1992)
The French Army's Plan XVII at the outbreak of the war involved swift mobilization followed by an immediate attack to drive the Germans from Alsace and Lorraine. If the British Expeditionary Force (BEF) joined in accordance with their Allied treaty, they would fill the left flank. Their Russian allies in the East would have a massive army, more than 95 divisions, but their mobilization would inevitably be slower. Getting their men to the front would itself take time because of their relatively sparse and unreliable railway network (for example, 75% of Russian railways were still single-tracked). Russia intended to have 27 divisions at the front by day 15 of hostilities and 52 by day 23, but it would take 60 days before 90 divisions were in action. Despite their difficulties, the Russians promised the French that they would promptly engage the armies of Austria-Hungary in the south and on day 15 would invade German East Prussia.Herwig, H. L. (1997). The First World War, Germany and Austria-Hungary 1914–1918. London, Arnold. p. 53.
According to Prit Buttar, "In addition to the fortifications amongst the Masurian Lake District, the Germans had built a series of major forts around Königsberg in the 19th century and had then modernised them over the years. Similarly, major fortresses had been established along the Vistula, particularly at Thorn (now Toruń). Combined with the flexibility provided by the German railways, allowing General Maximilian von Prittwitz to concentrate against the inner flanks of either Russian invasion force, the Germans could realistically view the coming war with a degree of confidence."
The Russians would rely on two of their three railways that ran up to the border; each would provision an army. The railways ended at the border, as Russian trains operated on a different rail gauge from Western Europe. Consequently, its armies could be transported by rail only as far as the German border and could use Prussian railways only with captured locomotives and rolling stock. The 1st Army would use the line that ran from Vilnius, Lithuania, to the border southeast of Königsberg. The 2nd Army railway ran from Warsaw, Poland, to the border southwest of Königsberg. The two armies would take the Germans in a pincer. The Russian supply chains would be ungainly becausefor defenseon their side of the border there were only a few sandy tracks rather than proper macadamized roads. Adding to their supply problems, the Russians deployed large numbers of cavalry and Cossacks; every day each horse needed ten times the resources that a man required.
The 1st Army commander was Paul von Rennenkampf, who in the Russo-Japanese War had earned a reputation for "exceptional energy, determination, courage, and military capability".Gourko, G.B. (1918) Memories & Impressions of War and Revolution in Russia, 1914–1917. London, John Murray. pp. 10–11. The 1st Army was mobilized from the Vilno Military District, and consisted of four infantry corps, five cavalry divisions and an independent cavalry brigade. The 2nd Army, commanded by Alexander Vasilyevich Samsonov, was mobilized from the Warsaw Military District, and consisted of five infantry corps and four cavalry divisions. These two armies formed the Northwestern Front facing the Germans, under the command of Yakov Zhilinsky. The Southwestern Front, facing the Austro-Hungarians in Galicia, was commanded by Nikolai Iudovich Ivanov.
Communications would be a daunting challenge. The Russian supply of cable was insufficient to run telephone or telegraph connections from the rear; all they had was needed for field communications. Therefore, they relied on mobile wireless stations, which would link Zhilinsky to his two army commanders and with all corps commanders. The Russians were aware that the Germans had broken their ciphers, but they continued to use them until war broke out. A new code was ready but they were still very short of codebooks. Zhilinsky and Rennenkampf each had one; Samsonov did not.Norman, B. (1973). Secret Warfare: the battle of codes and ciphers. Newton Abbot, David & Charles, p. 62. According to Prit Buttar, "Consequently, Samsonov concluded that he would have to take the risk of using uncoded radio messages."
Prelude: 17–22 August
Rennenkampf's 1st Army crossed the frontier on 17 August, moving westward slowly. This was sooner than the Germans anticipated, because the Russian mobilization, including the Baltic and Warsaw districts, had begun secretly on 25 July, not with the Tsar's proclamation on 30 July.McMeekin, S. (2011) The Russian Origins of the First World War. Harvard University Press, p. 67.
Prittwitz attacked near Gumbinnen on 20 August, when he knew from intercepted wireless messages that Rennenkampf's infantry was resting. German I Corps commanded by Gen. Hermann von François was on their left, XVII Corps commanded by Lt. Gen. August von Mackensen in the center and I Reserve Corps led by Gen. Otto von Below on the right. A night march enabled one of François' divisions to hit the Russian 20th Army Corps' right flank at 04:00. Rennenkampf's men rallied to stoutly resist the attack. Their artillery was devastating until they ran out of ammunition, then the Russians retired. I Corps attacks were halted at 16:00 to rest men sapped by the torrid summer heat. François was sure they could win the next day. On his left, Mackensen's XVII Corps launched a vigorous frontal attack but the Russian infantry held firm. That afternoon the Russian heavy artillery struck back—the German infantry fled in panic, their artillery limbered up and joined the stampede. Prittwitz ordered I Corps and I Reserve Corps to break off the action and retreat also.Citino, Robert M. The German Way of War: From the Thirty Years’ War to the Third Reich. Lawrence: University Press of Kansas, 2005.Bruce W. Menning – Bayonets before Bullets (Indiana University Press, 1992)