The Bug–Narew offensive from July 13 to August 27, 1915 was a major German victory during World War I on the Eastern Front. The Imperial German Army broke through 4 heavily fortified positions, inflicted defeats on superior enemy forces and pushed the Russian Army 300 km to the east, capturing 215,000 prisoners.Der Weltkrieg 1914 bis 1918. Berlin. 1932. Bd. 8. p. 340-509С.Г. Нелипович, 2022, p. 520-570 But the German army also suffered relatively heavy casualties, about 30,000 killed and missing.
Background The victories won by the armies of the Central Powers in the Gorlice–Tarnów offensive by the end of May 1915 prompted consideration of the development of success along the entire Eastern Front. On May 28, the Chief of German Great General Staff, General of Infantry Erich von Falkenhayn, defined the tasks of the German army of the Eastern Front in continuing the offensive: as holding Libava for the longest possible time, capturing Warsaw with the help of chemical weapons, and facilitating the operation in Galicia by attracting Russian forces. At the same time, the front on the Narew was no longer given much importance. The chief of staff of the Supreme Commander of All German Forces in the East, Lieutenant-General Erich Ludendorff, agreed only to conduct a new offensive on the Pilica River, transferring 4 divisions from Narew River to this sector. The Supreme Commander of All German Forces in the East, Field Marshal Paul von Hindenburg, was against any weakening along the entire German Eastern front. On June 2, Falkenhayn reported that the resistance of the Russian troops in Galicia had weakened, and there was no longer a need for a strike on Pilica river.Der Weltkrieg 1914 bis 1918 Bd. VIII.,1932, p.264-265
The question of the transition of the German Eastern Front to active operations was again discussed at the highest level on June 3–4 and 11. Falkenhayn this time put forward the idea of an offensive north of the Neman, using forces from the 9th Army, whose front near Warsaw was quite reliable. On June 20, Hindenburg agreed to a plan to resume the offensive against Mitava and Kovno, using reserves from the 8th Army and the army group of Max von Gallwitz, but subject to the simultaneous offensive of August von Mackensen's army group from the Vistula to the Bug and fleet operations against Riga.Der Weltkrieg 1914 bis 1918 Bd. VIII. p. 266
On June 28, two proposals were received at the Hindenburg headquarters in Lötzen: this time Falkenhayn conveyed the wish of Emperor Wilhelm II that the attack against Kovno serve as a cover for crossing the Vistula at the mouth of the Pilica, and Gallwitz proposed to strike at Przasnysz and Ciechanów. Hindenburg rejected both the Gallwitz plan, as directed against the heavily fortified part of the Russian front and Novogeorgievsk, and the idea of breaking through the 9th Army through several Russian defense lines. He, together with E. Ludendorff, proposed either to further strengthen the Mackensen's Army Group and refrain from attacking the armies of the Eastern Front, or to strike at the front of Kovno, Grodno.Der Weltkrieg 1914 bis 1918 Bd. VIII. p. 267-268
On June 30, Falkenhayn and the chiefs of staff of the armies of the Eastern Front arrived in Lötzen to discuss this project. Ludendorff now insisted on an offensive along the Neman River against Kovno, he was supported by Falkenhayn, who demanded to speed up the preparation of the operation. The chief of staff of the German 8th Army, Colonel D. von Schwerin, who proved the unprofitability of the attack on Osowiec Fortress and offered to shift the blow to Łomża and to the west, was not listened to. Also, Lieutenant Colonel G. Markvard, Chief of Staff of the Army Group Gallwitz, did not receive an answer about the plan to attack Przasnysz.Gallwitz M. von. Meine fuerertaetigkeit im Weltkriege 1914/1916. p. 264; Der Weltkrieg 1914 bis 1918 Bd. VIII. P. 268-269
However, Falkenhayn, after visiting Mackensen in Rava-Ruska and Archduke Friedrich in Pless, on July 2 conferred with Wilhelm II in Posen. The result was a directive dated 2 July (Signed by the Kaiser on July 3, but sent to headquarters the day before): “In addition to the great success in Galicia and the temporary improvement in the situation of Mackensen's troops. it is necessary to continue the offensive against Russia, limited in time and space of targets, so that the Supreme High Command at any time, in case of need, can quickly transfer large forces to another front. It is necessary to complete the operation in the East in 2 months. For this, a great military victory is needed through the close interaction of the Mackensen and Hindenburg army groups between the Bug, the Vistula and the Narew.Der Weltkrieg 1914 bis 1918 Bd. VIII. p. 271
The decision was influenced by the position of the chief of staff of the Austro-Hungarian Army Higher Command, Infantry General Franz Conrad von Hötzendorf. On June 28, he shared with Falkenhayn the idea to surround the Russian armies west of the Bug with a strike on Siedlce from the north and a broad offensive from the Vistula to the Bug from the south - along a 650-km arc. On July 1, the "Directives for the development of operations" were discussed by the commander-in-chief, Archduke Friedrich, Duke of Teschen, with Falkenhayn, and on July 2 - with Emperor Wilhelm II and received his approval.Oesterreich-Ungarns letzter Krieg 1914-1918. Wien. 1932. Hd. II. p. 611-612
On July 3, Supreme Commander of All German Forces in the East, Hindenburg ordered: the army of Remus von Woyrsch - to cover the operations of the Army Group Mackensen from Ivangorod and the mouth of the Pilica (river) and pursue the Russians in case of their retreat; 9th Army - to defend the left bank of the Vistula and advance along with the Woyrsch army through Warsaw and Novogeorgievsk if the Russians retreat; the army group of M. von Gallwitz to deliver the main blow to the Russian 1st Army and, after the breakthrough, go to Novogeorgievsk and the mouth of the Szkwa River, bearing in mind the exit to Siedlce; 8th Army - to assist the offensive of the Gallwitz group and join it; 10th Army - to cover the sector from Raygrod to the Neman River west of Kovno; Army of the Niemen - attack the Russian 5th Army to facilitate the task of the 10th Army. Gallwitz was informed the day before by Ludendorff and the Quartermaster General of Supreme Commander of All German Forces in the East, Lieutenant Colonel M. Hoffman, about the adoption of his project, about the intended goal of the offensive (offensive to Siedlce, that is, a breakthrough to a depth of 140 km, was replaced by a transition Narew from Pultusk to Różan and Ostrolenka).Gallwitz M., p. 268-269Der Weltkrieg 1914 bis 1918 Bd. VIII. p. 271, 279
Comparison of strength By July 5, the development of the "Haymaking" operation was completed at the Gallwitz's headquarters. The main blow to the west of Przasnysz was delivered by the XVII Reserve, XI and XVII Corps, to the east of Przasnysz the XIII and I Corps advanced. Artillery support was provided by 71 batteries of field guns, 39 batteries of light howitzers, 38 batteries of heavy howitzers, 6 batteries of 21 cm mortars, 5 batteries of 10 cm heavy guns, a battery of 15 cm naval guns (822 guns in total) and 56 mortars. There were 281,784 men. The German 8th Army, which contributed to the offensive on the Narew River(commanded by artillery general Friedrich von Scholtz), had 110,500 men in service and occupied positions from the Orzyc River to the Bobr River; it was less abundantly supplied with heavy artillery and shells.Sanitaetsbericht ueber das Deutsche Heer, bd. III, Berlin 1934, p. 43-44
Russian fortified positions consisted of four defensive lines, resting against the fortresses of Novogeorgievsk, Pultusk, Różan, Ostrolenka, Łomża, and Osowiec. The 1st Army of Cavalry General A. Litvinov defended the front from the banks of the Vistula River northeast of the mouth of the Narew to the Omulew Rivers. From the Omulew River to the Bobr River, the 12th Army of Infantry General A. Churin defended. In the 1st Army there were 378,095 men, in the 12th Army - 212,082 men. The defense of this sector of the front had to be reliable: the Russian troops had a significant superiority in manpower, both armies had 767 machine guns and 2,328 guns, but more than half of the artillery was in the fortresses of Novogeorgievsk (1,164) and Osowiec (96).С.Г. Нелипович, 2022, p. 510
The defense of the Vistula from the Narew River to the mouth of the Pilica River, including Warsaw, was entrusted to the 2nd Army of Infantry General V. Smirnov, numbering 172,941 men with 187 machine guns and 322 guns. There were 3,222 men and 66 guns in the Warsaw Alexander Citadel.С.Г. Нелипович, 2022, p. 510 Opposing these forces, the German 9th Army, Field Marshal Prince Leopold of Bavaria, gradually turned into a source of replenishment for strike groups. 143,722 men remained in it.Sanitaetsbericht ueber das Deutsche Heer, bd. III, Berlin 1934, s. 45
First phase of the German offensive: Russian defense breakthrough
Second phase: Battle for the initiative
Third phase: Fall of Novogeorgievsk
Fourth phase: general retreat of the Russian armies Russian troops retained a numerical advantage over the Germans, the supply of shells made it possible to conduct an intense battle for several days. However, the German and Austro-Hungarian troops of the army of Remus von Woyrsch managed to force the Vistula River above Ivangorod and create a threat to the rear of the Ivangorod fortress and the Russian 2nd Army. On August 2, M. Alekseyev gave the order to stubbornly defend the line of Warsaw forts and Praga (a suburb of Warsaw on the right bank of the Vistula River), but in the evening he ordered to withdraw the 2nd Army on the night of August 3 to the right bank of the Vistula, retaining only the line of forts, but not waging a stubborn battle on it, but only, if possible, delaying the Germans. As a result, both the 1st and 12th Russian armies had to take measures for the timely withdrawal of units so as not to be cut off by the breakthrough of the armies of the Central Powers from the south. The garrison of the Novogeorgievsk fortress, now subordinate directly to M. Alekseyev; on August 3, it began to be withdrawn from advanced positions to the forts of the outer bypass. Covering the withdrawal of the 2nd, 4th and 3rd armies was assigned to the 1st and 12th armies.С.Г. Нелипович, 2022, p. 534
In the Russian 12th Army on August 3, a stubborn battle continued along the entire front, while the 4th Siberian Army Corps was again thrown back. German troops captured 2,000 prisoners and 14 machine guns.Gallwitz M. von, 1929, p. 313-314
On August 4, after 14:00, the Germans attacked with large forces and broke through the positions of the 1st Siberian Army Corps and threw back the left flank of the 1st Siberian Army Corps of the 12th Army. The losses suffered were so great that at midnight on August 5, the commander of the 1st Army ordered the right flank of the army to be withdrawn with the withdrawal of the IV Corps to the army reserve. During the day the German onslaught continued. Actions in the sector of the 12th Army were also fierce. On August 4-5, Russian troops stubbornly defended their positions along the Orzyc river, constantly conducting counterattacks, but by the evening they were pushed back. On the night of August 5, Russian troops of the 2nd Army left Warsaw, blowing up railway stations and bridges across the Vistula River. In the morning, the troops of the German 9th Army, led by Field Marshal Prince Leopold of Bavaria, entered the capital of the Kingdom of Poland.Der Weltkrieg 1914 bis 1918 Bd. VIII. p. 340