Operation Blue: the Nazi conquest of the Caucasus

The blue operation (“Fall Blau” or “Unternehmen Blau”) was called to be the key that facilitated Nazi conquest of the Caucasus and access to its important natural resources. Control of Caucasian oil was one of the goals of the Nazi regime, which in mid-1942 was at a turning point in World War II.

However, despite the military successes initially achieved by the Wehrmacht, Operation Blue would end up becoming a huge fiasco for Nazi Germany. Furthermore, the battle for the Caucasus would end up being overshadowed by the Battle of Stalingrad, which also ended unfavorably for German arms.

Historic context

In June 1941 Nazi Germany had invaded the Soviet Union. The so-called Barbarossa operation had meant the destruction of a significant number of Red Army units and the occupation of large territories. The Germans had advanced to the outskirts of Leningrad and Moscow. However, the operation failed in its goal of destroying the Soviet Union, which was still in a position to resist.

To this fact was added the entry into the war of the United States, in December 1941. Sensing that the war was going to last longer than initially expected, the high command of the army calibrated new objectives in the East.

Objectives and plan of operations

In April 1942 Hitler issued his directive No. 41, which would become known as “Fall Blau” (Case Blue). The new goal of the Wehrmacht on the Eastern Front would be the conquest of the Caucasus and the oil fields. This region concentrated 80% of the oil production of the entire Soviet Union, and was also an important source of minerals. This would make it possible to replace Romania as the main supplier of fuel, whose production had already reached peaks and was beginning to show signs of exhaustion.

German forces in the South would be divided into two army groups: Army Group A would group 17th Army and 1st Panzer Army and Army Group B would group 6th Army and 4th Army Panzer. The ground forces had air support, provided by Luftflotte 4 (which had two air corps), and the collaboration of Hungarian and Romanian divisions.

In a first phaseThese forces would advance from their bases in the eastern Ukraine to the Don River and surround the Soviet armies, reaching Stalingrad; with it, they would cut the communications of the Caucasus with the central Russia. In a second phase, the German units would attack the strategic city of Rostov and the motorized formations would advance on the oil fields of Maykop, Grozny and Baku. It was expected to reach the borders with Iran and Turkey, forcing the latter to enter the war in favor of the Axis Pact. In anticipation of the capture of the oil fields, several German-owned oil companies had already been formed and a pool of skilled workers was available.

Start of operations

Operation Blue began on June 28, 1942well into the summer period. The Soviets had already suffered a heavy defeat around Kharkov during the month of May, so they adopted the strategy of giving ground to gain time.

During the first day of the offensive the Germans advanced several tens of kilometers, easily pushing their enemy. German pressure continued and by early July they had already reached the banks of the Don River in the Voronezh-Ostrogozhsk sector. After heavy fighting the Wehrmacht managed to conquer part of the city of Voronezhalthough it met strong resistance. The commander of the German armies in the South, Marshal von Bock, wanted to eliminate the surviving Soviet forces before continuing his advance to the Volga. But Hitler disagreed and, after a heated argument, dismissed von Bock witheringly.

At this point, the Soviet High Command erroneously assessed the possibility that the German offensive was targeting Moscow. Due to this, the defense of the Voronezh sector was reinforced, neglecting the southern sectors of the USSR. It would not be until a few weeks later that they realized what the German strategy was.

These German victories on the Don coincided with the capture of the Sevastopol naval base, on July 3, which was taken after a long siege of more than eight months. This ensured German control of the Crimean peninsula and added a point of optimism to the development of operations in the Caucasus.

Rostov, the gateway to the Caucasus

Rostov was a key objective for the conquest of the Caucasus, for being a communications hub and an important urban center. The Germans had already briefly occupied the city at the end of 1941, in the context of Operation Barbarossa, before being dislodged by the Red Army. Since then, the Soviets had managed to retain control of Rostov.

By July 19, 1942, German armored vanguards began to arrive on the outskirts of Rostov. The Soviet forces inside had to face pressure from both the West and the North, with the Don River behind them. Although the units of the Red Army offered some resistance, the Wehrmacht was imposing itself as the days went by. Some Soviet commands ended up ordering the withdrawal of the units to the other side of the Don River, including those defending Rostov.

By the 23rd the city was under German control, which thereby managed to dominate what was considered the gateway to the Caucasus. German propaganda celebrated this conquest as a major military triumph, many then believing that the conquest of the Caucasus would be little more than a military parade. In the Soviet zone, on the other hand, the news fell like a bucket of cold water and, as the war correspondent Alexander Werth later pointed out, generated a great commotion among the population (Werth, 1969: 468-469).

To the conquest of the Caucasus

Before the first victories that the Wehrmacht obtained, Hitler and some German commanders thought that the Red Army had already been defeated. Under this premise, and without having completed the first phase of the Blue operation, a variation was introduced in the plans for the conquest of the Caucasus. Codenamed Operation “Edelweiss,” the bulk of the German forces were to head south of the Don River and into Transcaucasia.

Hitler’s new orders created a serious problem for the logistics system of the German army, which was already facing a complicated situation in Soviet territory. Later, this new situation will turn against the Germans. The advance towards Stalingrad was not suppressed, but the plan was considerably altered.

Blitzkrieg is back

Between the end of July and the end of August Blitzkrieg operations were developed, or “lightning war”. To the west, on the Kuban peninsula, a good number of cities fell into German hands, without encountering strong resistance. To the east, a reconnaissance patrol from the 16th Motorized Infantry Division managed to reach the Caspian Sea, near Astrakhan (Messenger, 1991: 203). Another notable success was the conquest of Elista, the capital of the Republic of Kalmykia, in mid-August.

in the North Caucasus one of the key objectives of the German advance was the city of Maykop, an important center of oil production. By August 7, the vanguards of the 13th Panzer Division had reached the north of the city (Higgins, 2014: 55). However, it was going to be special commandos – the so-called “Brandenburgers” – who would stand out in taking the key points. Finally, on the afternoon of the 9th, the 13th Panzer Division managed to take the city and the airfield, also capturing some 1,000 prisoners (Black, 2007: 521). The Soviets had to withdraw, although they managed to destroy or disable a large part of the oil fields.

The Nazi high command welcomed the news of Maykop’s capture, but serious problems soon became apparent. Despite repair work, the damage was too severe to benefit production (Black, 2007: 522-523). On the other hand, it began to become apparent that the Germans, no matter how fast they advanced, would not be able to capture the remaining oil fields intact.

Road to Stalingrad

As the bulk of the German forces moved south, the German High Command adopted Operation ‘Fischreiher’, by which the 6th Army would advance alone towards Stalingrad. His units continued to press on and broke through the bend in the Don River. Initially, the Soviets put up strong resistance at the Kalach bridgehead, but eventually withdrew after suffering heavy losses.

On the afternoon of August 23, a motorized advance party of the 6th Army reached the Volga River north of Stalingrad at Rynok. River traffic was interrupted and the railway linking the Caucasus with central Russia was also cut. The bulk of the German forces had not yet arrived, so the town center was not initially assaulted. Nevertheless, the Luftwaffe focused during those days on bombing the city until reduced to rubble, causing about 25,000 dead civilians (Roberts, 2006: 143).

When the Germans decided to storm Stalingrad, they met solid and well-organized Soviet resistance. Over the next few months, what would later become known as the Battle of Stalingrad became a cancer on German military resources and, moreover, ended up eclipsing the Caucasus offensive itself.

Soviet resistance consolidates

Towards the end of August the forces of Army Group A were engaged in too many offensives at the same time. In the West they tried to reach the port of Tuapse and control the Black Sea coast; in the East they tried to reach Grozny and continue their advance to Baku; Between both axes of advance, Hitler’s armies also tried to reach Vladikavkaz and Ordzhonikidze, to continue towards Georgia.

Despite the retreat his forces had undertaken on the River Don, the Soviets planned to put up strong resistance in the Caucasus. They prepared a network of fortifications and defensive lines that, relying on the mountainous terrain of the area, would disrupt the German advance. Around Baku they established a powerful defensive ring and planned the destruction of oil infrastructure in case they were forced to withdraw from the area. In addition, they had in their favor the exhaustion of the Nazi offensive, whose motorized units faced serious fuel shortages.

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