|Battle of Tannenberg|
|Part of Invasion of East Prussia, Eastern Front of World War I|
German prisoners after the battle.
|Commanders and leaders|
| Mikhail Alekseyev|| Paul von Hindenburg|
| First Army||Eighth Army|
| 200,000 (First Army)|
230,000 (Second Army)
|Casualties and losses|
| 14,371 killed, 24,592 wounded|
Total casualties: 38,963 killed or wounded
| 31,865 killed, 46,783 wounded, 16,944 captured|
Total casualties: 95,592 killed, wounded, or captured; 120 field guns captured
The Battle of Tannenberg was a decisive engagement during the first year of World War I, from 26 to 30 August of 1914, between Russia and Germany. It saw the triumph of the Russian First Army and the Second Army over the German Eighth Army, as well as the capture of German general Erich Ludendorff and the death of Colonel Maximilian Hoffman. It was noted for the close cooperation and coordination of the First and Second Armies. Following the battle, Russian forces pushed further into East Prussia.
The Allied battle plan prior to the war had been based on France and the United Kingdom halting the German armies in the West while the huge Russian armies could be organized and brought to the Eastern Front. The numbers were overwhelming; in perhaps as little as a month, the Russians could field around ten complete armies, more men than the Germans could muster on both fronts put together.
Frustrating this plan was the Russians' lack of a good quality railroad network. Additionally, Russian trains operated on a different rail gauge to Germany, meaning that unless the Russians acquired German railroad engines and cars, their armies could only be transported by rail as far as the German border. The presence of the armies of Austria-Hungary to the south as well as initially those of Japan to the east limited Russia's involvement in the beginning (however, Japan declared war on Germany on 23 August 1914). Nevertheless, the Russians considered the Germans to be their primary threat, and planned to use limited forces to quickly seize East Prussia.
The Germans contrarily considered the Russians to be a secondary threat. The entire Schlieffen Plan was based on the idea of defeating France as quickly as possible, and then transporting their armies by train to the eastern front. This allowed the Germans to garrison Prussia fairly lightly with a single army, the Eighth, while the German Ninth Army was stationed in central Germany to reinforce either front. There was little allowance for anything other than a delaying action while the outcome in the west was decided. In order to delay the Russian forces as long as possible, the entire area around Königsberg (now Kaliningrad), near the Russian border, was heavily fortified with a long series of fieldworks.
Just prior to the opening of the war, the situation developed largely as prewar planning had expected. The German Eighth Army was in place southwest of Königsberg, while the two available Russian armies were located to the east (the First Army) and south (the Second Army); the latter in what was known as the "Polish Salient". Russian battle plans called for an immediate advance westward by the Russian First Army under General Mikhail Alekseyev into East Prussia, with Königsberg as the initial objective. The Russian Second Army under General Alexander Samsonov was to initially move westward around the Masurian Lakes and then swing north over a hilly area to cut off the Germans, who would by this point be forced into defending the area around Königsberg. If executed correctly, the Germans would be surrounded.
During the first weeks of the war, the situation developed largely according to the German plan. The Germans had moved up about half of the units of the Eighth Army, reinforced by small groups of the Königsberg garrison, to positions east of the city near the border. The Battle of Stallupönen, a small engagement by the German I Corps under Hermann von François, was unsuccessful, however. Nevertheless, the German theater commander, General Maximilian von Prittwitz, ordered a withdrawal towards Gumbinnen. A counterattack planned for 20 August had a fair chance of succeeding but François attacked prematurely, before Mackensen's XVII Corps and Below's I Reserve Corps arrived at their positions. Thus alerted to German intentions, the Russians moved their heavy artillery up and were able to turn the attack into a disordered retreat. The Battle of Gumbinnen forced the Germans, in many cases via rail, to take positions south of Königsberg.
Concerned by the defeat at Gumbinnen and the continued advance of the Russian Second Army from the south, Prittwitz ordered a retreat to the Vistula, effectively abandoning East Prussia. When he heard of this, Helmuth von Moltke, the German Army Chief of Staff, recalled Prittwitz and his deputy to Berlin. They were replaced by Paul von Hindenburg, who was called out of retirement, with Erich Ludendorff as his chief of staff.
Things were quite as dire as they seemed to the German commanders in Berlin. Samsonov and Alekseyev worked well together, and had good supply convoys prepared for the advance, advancing at their planned rate and frequently making communications. The staff of the two armies was quite competent, and they made good progress towards their objective.
And at the same time, the scale of the forces deployed still meant the Russians had the upper hand. As they were currently deployed, the German Eighth Army could not even cover the front along Samsonov's line of march, leaving Samsonov's left wing free to advance without opposition. Unless troops from the Königsberg area (I, XVII and I Reserve Corps), could be moved to check this advance, the Germans were in serious danger of being cut off. Alekseyev also called a number of divisions to aid the Second Army, as he did not immediately need them.
German consolidation of the Eighth Army
Colonel Max Hoffmann, Prittwitz's deputy chief of operations, not aware of the cooperation level between the Russian generals, and what it would likely mean for their plans. Guessing incorrectly that the Russian armies would continue to operate separately, Hoffmann proposed moving almost all German forces not already in Königsberg's eastern defense line to the southwest, moving I Corps by train to the left of Samsonov's line, a distance of over 160 km (99 mi). The XVII Corps and I Reserve Corps, at the time south of I Corps, would be readied for a move further south to face the Russian VI Corps on Samsonov's right flank. The German 1st Cavalry Division would remain as a screen just south of the eastern edge of the Königsberg defenses, facing Alekseyev's First Army. The eastern portion of the Königsberg defenses was the only part that was fully manned, while the approaches from the south were entirely open.
In theory, the plan was extremely risky. If the First Army turned to the southwest instead of advancing directly westward toward Königsberg, they would appear on the Eighth Army's extreme left flank, allowing for either a counterattack against the Eighth, or alternately turn north toward Königsberg from the undefended south. However, Hoffmann was convinced of the soundness of his plan, both because he was not aware of the friendship between the Russian generals, and also because of the Russian habit of transmitting the next day's orders over unencrypted radio communications. It appears the Russians had outrun their secure telegraph landlines, and were short of trained wireless telegraph operators and cryptographic equipment. This forced them to transmit their messages en clair, and these were easily intercepted and translated by the Germans.
When Hindenburg and Ludendorff arrived on 23 August, they immediately stopped the retreat and put Hoffmann's plan into action. Since Prittwitz had already ordered the German troops to pull back via train, Ludendorff directed I Corps to alight near Deutsch-Eylau to cover the left flank of XX Corps, who had been in front of the Second Army since before the battle at Gumbinnen. Hoffmann had already issued similar orders, so little confusion resulted. The trap was being set.
Ludendorff also learned at this point that von Moltke had decided to take three corps and a cavalry division from the Western front and redeploy them to East Prussia. Ludendorff protested that they would arrive too late to have any effect, while at the same time weakening the German offensive through Belgium against France. However, von Moltke considered East Prussia too politically important to lose, and ignored Ludendorff's protests. Later, this movement of German forces would be seen as the final undoing of the Schlieffen Plan that demanded a considerable preponderance of local forces in a rapid encirclement and destruction of the French armies east of Paris as they were driven onto the German anvil on the Franco-German border.
Early phases of the battle
Starting on 22 August, Samsonov's forces had met the Germans all along their front, and had successfully pushed them back in several places. On the 23rd, they attacked the German XX Corps, which retreated to the Orlau-Frankenau line that night. The Russians followed, and on the 24th they met them again at Orlau-Frankenau, where the now-entrenched XX Corps temporarily stopped the Russian advance. Once again XX Corps retreated in order to avoid possible encirclement by superior forces. Undeterred, Samsonov saw this as a wonderful opportunity to cut this unit off completely, because, as far as he was aware, both of his flanks were unopposed. He ordered most of his units to the northwest, toward the Vistula, leaving only his VI Corps to continue north towards their original objective of Seeburg.
Concerned about this possible flanking maneuver, Ludendorff issued an order to François' now-deployed I Corps to initiate the attack on Samsonov's left wing at Usdau on 25 August. François rejected this direct order, stating there was no way to have the corps ready in time and that he wanted to wait until his artillery support was ready on 27 August. Ludendorff and Hoffmann would have none of this, and traveled to meet François to repeat the order in person. François agreed to commence the attack, but complained of a lack of artillery shells, telling his superiors that his troops would be obliged to charge with bayonets.
On the way back from the meeting, Hoffmann received new radio intercepts. Rennenkampf's most recent orders stated the next day's offensive would continue due southwest, helping Samsonov, against Hoffmann's gamble. The Russian First Army was now a serious concern as it advanced to aid the Second Army. A second intercept of Samsonov's own plans made it clear that he would continue his own march northwest, having concluded that the Germans would continue to retreat in front of Tannenberg. It was planned that the two armies would meet up in front of Tannenberg and continue a unified offensive.
Ludendorff and Hindenburg were doubtful that these intercepts were real, finding it difficult to believe that even one Russian commander would send his messages in the clear, let alone two. Nevertheless they were eventually convinced they were indeed real, and the plans were put into action, though not according to how they initially thought. Their gamble proved to be wrong; the two Russian armies were working in coordination. I Corps would open its attack on the Russian left flank on 25 August, while orders were sent to XVII Corps to move south and meet the Russian right flank as soon as possible. They had no troops to counter the First Army with, which would cut them off from the forces at Königsberg and attack from the northwestern flank. They had no way to cover this attack as there were no troops for it.
Given that the need for immediate action was pressing, François decided against waiting for artillery supplies, allowing the battle to open on 27 August as he had wished.
The morning of the 26th opened with the First Russian Army advancing southwesr towards Tannenberg, meeting little resistance. The troops that were formerly directly in front of them had moved to the south, facing the Second Army's right flank. There was still time to block the gap between the Russian armies and thereby protect the German movements, which by this point were being reported back to Russian headquarters. Nevertheless, on the night of the 25th, the German field commander gave orders to continue as planned, as there were not enough troops to actually stop the First Army's advance to the Second Army.
Due to François' delays, XVII German Corps opened the battle proper. They met the two separated divisions of VI Russian Corps near Seeburg and Bischofstein, and failed to stop them, forced to retreat. The right flank of the Second Russian Army was still closed. In the meantime, the Russian advance toward Tannenberg continued to be blocked by XX German Corps in front of them. Their additional success was in the center, where XIII Russian Corps advanced toward Allenstein unopposed.
François opened his own attack on the Russian right again on the 27th, held by reinforced VI Russian Corps. His artillery proved to be useless, as they did not have enough supplies, and by that night the Germans were forced to fall back again. In order to help stabilize the line, Ludendorff ordered the I Corps to abandon the left and turn southwest to help break through at Tannenberg. It also failed. By the time this maneuver was complete, the bulk of the Russian Second Army were all in the Tannenberg area, consisting of the newly arrived XIII, XV, and part of XXIII Corps.
Failure to break the right flank and leaving the left flank virtually unopposed resulted in the First Army arriving and destroying the combined German I and XVII Corps, with François retreating and barely surviving. By this time, due to his battle plan being a failure, Hoffman committed suicide outside his headquarters by shooting himself. Ludendorff reported the failures to von Hindenburg, who was outraged, but ordered them to proceed.
By the evening of 28 August, the full extent of the danger to the Germans was evident. The Russian I Corps on the left and VI Corps on the right were both advancing. Meanwhile the center was also retreating and could no longer hope to maintain the line. Ludendorff had no option but to order a retreat to the west and attempt to reorganize. Meanwhile, Alekseyev contacted Samsonov to send several divisions around the German units meet up behind them, closing them off in an encirclement. The First Army arrived from the north and began joining the Second.
François and his retreating survivors met up on 29 August in a pocket near Tannenberg that was now surrounded by almost the full force of the Russian armies. Ludendorff and his headquarters was trapped as well in this encirclement. Artillery fire kept the Russians from mounting an effective offensive at first, though soon their supplies of ammunition ran out and they were forced to engage the infantry. The cavalry screen that was supposed to delay the First Army had moved in and attempted to break through their lines, though failed as it was greatly outnumbered.
Ludendorff sent a final radio message to Hindenburg telling him of the impending defeat. He replied that he did not have any forces to spare to send to the aid of Ludendorff's doomed divisions. The Russian advance began and the Germans were slowly defeated in the encirclement, and many simply surrendered.
By the time the battle ended on 30 August, Ludendorff's force had taken 31,865 killed and 46,783 wounded. Another 16,944 were captured. Along with that, a total of 120 field guns were captured by the Russians as well. Ludendorff himself was among the prisoners. Hindenburg now called in his last available units to stall the now-unhindered Russian advance to the west, and von Moltke, who was informed by Hindenburg, ordered the mobilization of the Ninth Army, which was previously held in reserve.
The Second and First Armies continued to advance to the west, now clear of the Eighth Army, the remains of which (some 54,000 odd troops) were retreating in disarray. The Ninth Army met them and a battle occurred, but the Russian Tenth Army also joined into the assault, bringing their total troop count up to more than a half a million men. This was heavily propagandized by the Russian government and Allied countries, and raised the morale of the populations while being a devastating blow to German morale.
Meanwhile, Samsonov and Alekseyev became known as the "Герои Танненберга" ("Heroes of Tannenberg").