Consolidation of the German 8th Army The new commanders arrived at Marienburg on the afternoon of 23 August; they had met for the first time on their special train the previous night and now they rendezvoused with the 8th Army staff. I Corps was moving by the rail line, and Ludendorff had previously counter-ordered it further east, at
Deutsch-Eylau, where it could support the right of
XX Corps. XVII Corps and I Reserve Corps would march towards the left of XX Corps. Ludendorff had delayed their marches for a day to rest while remaining in place should Rennenkampf attack. The German 1st Cavalry Division and some garrison troops of older men would remain as a screen just south of the eastern edge of the Königsberg defenses, facing Rennenkampf's 1st Army. Hindenburg summarized his strategy, "We had not merely to win a victory over Samsonov. We had to annihilate him. Only thus could we get a free hand to deal with the second enemy, Rennenkampf, who was even then plundering and burning East Prussia." The new commander had raised the stakes dramatically. They must do more than stop Samsonov in his tracks, as they had tried to block and push back Rennenkampf. Samsonov must be annihilated before they turned back to deal with Rennenkampf. For the moment Samsonov would be opposed only by the forces he was already facing, XX Corps, mostly East Prussians who were defending their homes. The bulk of the Russian 2nd Army was still coming towards the front; if necessary, they would be allowed to push further into the province while the German reinforcements assembled on the flanks, poised to encircle the invaders—just the tactics instilled by Schlieffen.
Early phases of battle: 23–26 August Zhilinsky had agreed to Samsonov's proposal to start the 2nd Army's advance further westward than originally planned, separating them even further from Rennenkampf's 1st Army. On 22 August Samsonov's forces encountered Germans all along their front and pushed them back in several places. Zhilinsky ordered him to pursue vigorously. They already had been advancing for six days in sweltering heat without sufficient rest along primitive roads, averaging a day and had outrun their supplies. On 23 August they attacked the German XX Corps, which retreated to the Orlau-Frankenau line that night. The Russians followed, and on the 24th they attacked again; the now partially entrenched XX Corps temporarily stopped their advance before retreating to avoid possible encirclement. At one stage the chief of staff of the corps directed artillery fire onto his own dwelling. Samsonov saw a wonderful opportunity 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. He did not have enough aircraft or skilled cavalry to detect the German buildup on his left. Rennenkampf mistakenly reported that two of the German Corps had sheltered in the Königsberg fortifications. On 24 August Hindenburg, Ludendorff and Hoffmann motored along the German lines to meet Scholtz and his principal subordinates, sharing the roads with panic-stricken refugees; in the background were columns of smoke from burning villages ignited by artillery shells. They could keep control of their army because most of the local telephone operators remained at their switchboards, carefully tracking the motorcade. Along the way they drove through the village of
Tannenberg (today called Stębark), which reminded the two younger men of the
defeat of the Teutonic Knights there by the Poles and Lithuanians in 1410; Hindenburg had been thinking about that battle since the evening before when he strolled near the ruins of the castle of the Teutonic Order. (In 1910 Slavs had commemorated their triumph on the
old battlefield.) Aided by Russian radio intercepts, a captured map of Russian positions, and information from fleeing German civilians of Rennenkampf's slow progress, Hindenburg and Ludendorff planned the encirclement of the Russian 2nd Army. I Corps and XX Corps would attack from
Gilgenburg towards Neidenburg, while XVII Corps and I Reserve Corps attacked the Russian right flank. They met with Scholtz and his XX Corps staff on 24 August, and François on 25 August, where he was ordered to attack towards
Usdau on 26 August. François stated only part of his corps and artillery had arrived. Ludendorf insisted the attack must go forward as planned, since more trains were expected beforehand. François replied, "If it is so ordered, of course an attack will be made, and the troops will obviously have to fight with bayonets." On the way back to headquarters Hoffmann received new radio intercepts. Rennenkampf's most recent orders from Zhilinsky were to continue due west, not turn south-westward towards Samsonov, who was instructed to continue his own drive northwest further away from Rennenkampf. Based on this information Scholtz formed a new defensive flank along the
Drewenz River, while his main line strengthened their defenses. Back at headquarters Hindenburg told the staff, "Gentlemen. Our preparations are so well in hand that we can sleep soundly tonight." Samsonov was concerned by the German resistance with their earlier advance, and aerial reconnaissance spotted the arrival of the German I Corps. Zhilinsky and Samsonov could not reach an agreement on the direction of the army. The dispute over the direction of attack resulted in a compromise: on the 24th, the 2nd Army was sent to the AllensteinOsterode front, leaving the VI Corps on the move to
Bischofsburg at Zhilinsky's request, i.e. separating it from the rest of the army by 2½ marches and thereby exposing it to a separate defeat. These negotiations, as well as the negotiations about a day's rest, which Samsonov insistently demanded, led to the fact that, apart from the VI Corps, the army barely moved on the 25th. The order from Zhilinsky was to attack northwest as per Samsonov's aim, with Martos' XV Corps and Klyuev's XII Corps, while I Corps protected the left flank, and VI Corps was positioned on the right at Bischofsburg.
Main battle: 27–30 August Zhilinsky was visited by the commander of the Russian Army, the
Grand Duke Nicholas Nikolaevich of Russia, who ordered him to support Samsonov. François commenced his attack early on the 25th, with his 1st Infantry Division advancing towards Seeben, his 2nd Infantry division on its southern flank, and the rest of his corps arriving by train during the day. He captured Seeben by mid-afternoon, but saved an advance on Usdau for the next day. North of François, Scholtz's 37th and 41st Infantry Divisions faced the Russian 2nd Infantry Division, which fell back with heavy losses. On the left flank of Scholtz's XX Corps, Curt von Morgen's 3rd Reserve Division was ordered to advance onto Hohenstein, but held back out of concern that the Russian XV and XII Corps would threaten his left flank. Klyuev's Russian XIII Corps was ordered to advance onto
Allenstein. On Samsonov's right flank, Alexander Blagoveschensky's Russian VI corps soon faced Mackensen's German XVII Corps and von Below's German I Reserve Corps. Von Below, to the right of Mackensen, advanced to cut the road between Bischofsburg and Wartenburg. Blagoveschensky's 16th Infantry Division occupied Bischofsburg, while his 4th Infantry Division was north of Rothfliess, and his 4th Cavalry division was at Sensburg. The 16th Infantry division was ordered to move towards Allenstein, while the 4th Infantry Division was split between Lautern and Gross-Bössau. Mackensen's 36th Infantry Division, on the right, and his 35th infantry Division, on the left, advanced towards Bischofsburg. The Russian 4th Infantry Division suffered heavy losses and retreated towards
Ortelsburg. In an attempt to send reinforcements, Blagoveschensky split the 16th Infantry Division between Bischofsburg and Ramsau. However, they were met in the flank and rear by von Belows's I Reserve Corps, and retreated in disarray. during the fight at Usdau on 27 August That evening the 8th Army's staff was on edge. Little had been achieved during the day, when they had intended to spring the trap. XX Corps had done well on another torrid day, but now was exhausted. On their far left they knew that XVII Corps and I Reserve Corps were coming into action, but headquarters had learned little about their progress. In fact, XVII Corps had defeated the Russian VI Corps, which fled back along the roads. XVII Corps had endured long marches in sweltering weather, but some men still had the energy to pursue on bicycles requisitioned from civilians. Hoffmann, who had been an observer with the Japanese in Manchuria, tried to ease their nerves by telling how Samsonov and Rennenkampf had quarreled during that war, so they would do nothing to help one another. It was a good story that Hoffmann treasured and retold frequently. In Hindenburg's words "It was now apparent that danger was threatening from the side of Rennenkampf. It was reported that one of his corps was on the march through Angerburg. It is surprising that misgivings filled many a heart, that firm resolution began to yield to vacillation, and that doubts crept in where a clear vision had hitherto prevailed? We overcame the inward crisis, adhered to our original intention, and turned in full strength to effect its realization by attack." The German right flank would advance to Neidenburg, while von Below's I Reserve Corps advanced to Allenstein, and Mackensen's XVII Corps chased Blagoveschensky's retreating VI Corps. François was ready to attack the Russian left decisively on 27 August, hitting the Russian
1st Army Corps. His artillery barrage was overwhelming, and soon he had taken the key town of Usdau. In the center the Russians continued to strongly attack the German XX Corps and to move northwest from Allenstein. The German XVII Corps and I Reserve Corps pushed the Russian right wing they had bloodied the day before further back. Gen. Basil Gourko (
Vasily Gurko), commanding the Russian 1st Army Cavalry Division (and from 1916 to 1917 chief of the general staff), was told later that Samsonov was not aware of what was happening on his flanks because he was observing the action from a rise in the ground a distance from his wireless set and reports were not relayed to him. On the evening of the 27th, the Germans gave an order for encirclement, the essence of which is set out in the following report from Ludendorff to the high command: "The Russian
1st Army Corps has been thrown back from Gilgenburg to Soldau. The Russian 6th Army Corps has been thrown back from Bischofsburg to Ortelsburg. Parts of the
23rd Army Corps have been defeated and are retreating to Neidenburg. The 13th and 15th Army Corps still occupy the Hohenstein, Allenstein region, and will be attacked tomorrow, if possible, from all sides". On the morning of 28 August the German commanders were motoring along the front when they were shown a report from an aerial observer that Rennenkampf's army was moving towards their rear. Ludendorff announced that the attack on the 2nd Army must be broken off. Hindenburg led him behind a nearby hedge; when they emerged Hindenburg calmly said that operations would continue as planned. Later radio intercepts confirmed Rennenkampf was still slowly advancing on Königsberg. François' I Corps resumed his assault on the Russian 1st Army Corps, taking Soldau by late morning, and then advancing onto Neidenburg, as the Russian 1st Army Corps became an ineffective force in the battle. Scholtz's XX Corps, to the north, also advanced. Though his 41st Infantry Division was badly mauled by Martos' Russian 15th Army Corps, it held its ground, while the German 37th Infantry Division reached Hohenstein by the end of the day. The German 3rd Reserve Division was also able to advance on the Russian 15th Army Corps, forcing Samsonov to order a retreat to Neidenburg. Von Below's German I Reserve Corps engaged Klyuev's Russian 13th Army Corps west of Allenstein, and became isolated. Klyuev received orders from Samsonov to retreat towards Kurken. Mackensen's German XVII Corps continued pursuing the retreating Russians. One half of the German encirclement was complete by the end of the day, as Ludendorff wrote, "The enemy front seemed to be breaking up... We did not have a clear picture of the situation with individual units. But there was no doubt that the battle was won." On 29 August, François' cavalry regiment reached
Willenberg by evening, while his 1st Infantry Division occupied the road between Neidenburg and Willenberg. François' I Corps patrols linked up with Mackensen's German XVII Corps, who had advanced to Jedwabno, completing the encirclement. On 29 August the troops from the Russian 2nd Army's center who were retreating south ran into a German defensive line. Those Russians who tried to break through by dashing across open fields heavy with crops were mowed down. They were in a cauldron centered at
Frogenau, west of
Tannenberg, and throughout the day they were relentlessly pounded by artillery. Many surrendered – long columns of prisoners jammed the roads away from the battleground. Hindenburg and Ludendorff watched from a hilltop, with only a single field telephone line; thereafter they stayed closer to the telephone network. Hindenburg met one captured Russian corps commander that day, another on the day following. On 30 August the Russians remaining outside of the cauldron tried unsuccessfully to break open the snare. Rather than report the loss of his army to
Tsar Nicholas II, Samsonov disappeared into the woods that night and committed suicide. His body was found in the following year and returned to Russia by the Red Cross. On 31 August Hindenburg formally reported to the Kaiser that three Russian army corps (13th, 15th and 23rd) had been destroyed. The two corps (1st and 6th) that had not been caught in the cauldron had been severely bloodied and were retreating back to Poland. He requested that the battle be named Tannenberg (an imaginative touch that both Ludendorff and Hoffmann claimed as their own). The 2nd Army lost approximately 120,000, but, taking into account the attacks, it continued to pose a threat to the Germans from the rear, it still had 116,791 men and 435 guns. The Russian command continued to be active on the flanks of the German 8th Army, which affected the fact that the Germans were unable to destroy the 1st in the
First Battle of the Masurian Lakes. The Germans suffered just 12,000 casualties out of the 150,000 men committed to the battle, incl. 1,888 killed, 6,579 wounded and 4,588 missing. There is probably some data, since the authors who referred to the named lists of losses cannot single out the losses of officers. According to other estimates, the Hindenburg army lost 30,000 men. Sixty trains were required to take captured Russian equipment to Germany. The German official history estimated 50,000 Russians killed and wounded, which were never properly recorded. Another estimate gives 30,000 Russians killed or wounded, with 13 generals and 500 guns captured. The main reason for the defeat of the 2nd Army lies in Samsonov's neglect of radio communications, as a result of which they attacked blindly, and the Germans knew about his exact location. As noted, Samsonov could have avoided disaster, given that the first attempt to encircle the Russian army for the Germans ended in a bloody failure at Lake Waplitz, as a result of which the German XX Corps on the flanks was repulsed, and the 41st Division from its composition was partially destroyed. Samsonov, due to the fact that he went to the center of the position of his troops for personal encouragement of the latter, did not know about this. As a result, this very center was surrounded. ==Aftermath==