Case Blue (German: Fall Blau) was the Wehrmacht's plan for the 1942 summer offensive in southern Russia between 28 June and 24 November 1942, during World War II. The objective was to capture the oil fields of Baku (Azerbaijan SSR), Grozny and Maikop, to enable the Germans to obtain fuel and also to deny it to the Soviet Union, bringing about the complete collapse of the Soviet war effort.
After Operation Barbarossa failed to destroy the Soviet Union as a political and military threat the previous year, Adolf Hitler recognized that Germany was now locked in a war of attrition and he was also aware that Germany had a chronic fuel shortage and would not be able to continue attacking deeper into Soviet territory without more. Hitler ordered the preparation of offensive plans for summer 1942 to secure the Soviet oil fields in the Caucasus. The operation involved a two-pronged attack: one from the Axis right flank against the oil fields of Baku, known as Operation Edelweiss, and one from the left flank to protect the flank of the first attack, moving in the direction of Stalingrad along the Don River, known as Operation Fischreiher.
Army Group South (Heeresgruppe Süd) was divided into Army Group A and Army Group B (Heeresgruppe A and Heeresgruppe B). Army Group A was to fulfil Operation Edelweiss by crossing the Caucasus Mountains to reach the Baku oil fields, while Army Group B protected its flanks along the Volga by fulfilling Operation Fischreiher. Supported by 2,035 Luftwaffe aircraft and 1,934 tanks and assault guns, the 1,570,287-man Army Group South began the offensive on 28 June, advancing 48 kilometers on the first day and easily brushing aside the 1,715,000 Red Army troops opposite, who wrongly expected a German offensive on Moscow even after Blau commenced. The Soviet collapse in the south allowed the Germans to capture the western part of Voronezh on 6 July and reach and cross the Don River near Stalingrad on 26 July. Army Group B's approach toward Stalingrad slowed in late July and early August owing to constant counterattacks by new Red Army reserves and overstretched German supply lines. The Germans defeated the Soviets in the Battle of Kalach and the Battle of Stalingrad began in late August. Non-stop Luftwaffe bombing, artillery-fire and street fighting destroyed the city and inflicted many casualties on the Red Army. After three months of battle, the Germans controlled 90 percent of Stalingrad on 19 November.
In the south, Army Group A captured Rostov-on-Don on 23 July and swept south from the Don to the Caucasus, capturing the demolished oilfields at Maikop on 9 August and Elista on 13 August near the Caspian Sea coast. Determined Soviet resistance and the long distances from Axis sources of supply reduced the Axis offensive to local advances only and prevented the Germans from completing their strategic objective of capturing the main Caucasian oilfield at Baku. Luftwaffe bombers destroyed the oilfields at Grozny but attacks on Baku were prevented by the short range of the German fighters.
The Red Army defeated the Germans at Stalingrad, following Operation Uranus and Operation Little Saturn. This defeat forced the Axis to retreat from the Caucasus during the Battle of Caucasus to avoid being cut off by the Red Army, that was now advancing from Stalingrad towards Rostov. Only the Kuban region remained tentatively occupied by Axis troops.
Axis strategy
Background
On 22 June 1941, Germany launched Operation Barbarossa to defeat the Soviet Union in a Blitzkrieg which was expected to last only three months. The Axis offensive had met with initial success and the Red Army had suffered some of the greatest defeats in military history, before halting the Axis units just short of Moscow (November–December 1941). The Germans had captured vast areas of land and important industrial centers but the Soviet Union remained in the war. In the winter of 1941–1942, the Soviets struck back in several successful counter-offensives, pushing back the Germans from Moscow. Despite these setbacks, Hitler wanted the complete destruction of Russia, for which he required the oil resources of the Caucasus.
By February 1942 the German Army High Command (OKH) had begun to plan for a follow-up campaign to Barbarossa – with the Caucasus as its principal objective. On 5 April 1942, Hitler laid out the elements of the plan, now "Case Blue" (Fall Blau) in Führer Directive No. 41. The directive outlined the main goals of the 1942 summer campaign on the Eastern Front, holding attacks for Army Group Centre, the capture of Leningrad and the link-up with Finland for Army Group North and the capture of the Caucasus for Army Group South. The schwerpunkt (main effort) was to be in the south.
The oilfields
The Caucasus, a large, culturally diverse region traversed by its eponymous mountains, is bounded by the Black Sea to the west and the Caspian Sea to the east. The region north of the mountains was a production center for grain, cotton and heavy farm machinery, while its two largest oilfields, at Maikop, near the Black Sea, and Grozny, about halfway between the Black and the Caspian Seas, produced about 10 percent of all Soviet oil. South of the mountains lay Transcaucasia, comprising Georgia, Azerbaijan and Armenia. This industrialized and densely populated area contained some of the largest oilfields in the world. Baku, the capital of Azerbaijan, was one of the richest, producing 80 percent of the Soviet oil—about 24 million tons in 1942.
The Caucasus also possessed plentiful coal, peat, nonferrous and rare metals. Manganese deposits at Chiatura, in Transcaucasia, formed the richest single source in the world, yielding 1.5 million tons of manganese ore annually, half of the Soviet Union's total production. The Kuban region of the Caucasus also produced large amounts of wheat, corn, sunflower seeds, and sugar beets, all essential in the production of food.
These resources were of immense importance to the German war effort. Of the three million tons of oil Germany consumed per year, 85 percent was imported, mainly from the United States, Venezuela, and Iran. When war broke out in September 1939, the British naval blockade cut Germany off from the Americas and the Middle East, leaving the country reliant on oil-rich European countries such as Romania to supply the resource. An indication of German reliance on Romania is evident from its oil consumption; in 1938, just one-third of the 7,500,000 tons consumed by Germany came from domestic stocks. Oil had always been Germany's Achilles heel, and by the end of 1941, Hitler had nearly exhausted Germany's reserves, which left him with only two significant sources of oil, the country's own synthetic production and the Romanian oilfields, with the latter supplying 75% of Germany's oil imports in 1941. Aware of his declining oil resources, and fearful of enemy air attacks on Romania (Germany's main source of crude oil), Hitler's strategy was increasingly driven by the need to protect Romania and acquire new resources, essential if he wanted to continue waging a prolonged war against a growing list of enemies. In late 1941, the Romanians warned Hitler that their stocks were exhausted and they were unable to meet German demands. For these reasons, the Soviet oilfields were extremely important to Germany's industry and armed forces as the war became global, the power of the Allies grew, and shortages started to occur in Axis resources.
Planning
Axis forces
The German plan involved a three-staged attack:
- Blau I: Fourth Panzer Army, commanded by Hermann Hoth (transferred from Army Group Centre) and the Second Army, supported by the Second Hungarian Army, would attack from Kursk to Voronezh and continue the advance, anchoring the northern flank of the offensive towards the Volga.
- Blau II: Sixth Army, commanded by Friedrich Paulus, would attack from Kharkov and move in parallel with Fourth Panzer Army, to reach the Volga at Stalingrad (whose capture was not deemed necessary).
- Blau III: First Panzer Army would then strike south towards the lower Don River, with Seventeenth Army on the western flank and Fourth Romanian Army on the eastern flank.
The strategic objectives of the operation were the oilfields at Maykop, Grozny and Baku. As in Barbarossa, these movements were expected to result in a series of grand encirclements of Soviet troops.
The offensive was to be conducted across the southern Russian (Kuban) steppe utilizing the following Army Group units:
Northern Sector (Volga campaign)
Southern Sector (Caucasus campaign)
Soviet forces
The Soviet army command (Stavka) failed to discern the direction of the main German strategic offensive anticipated in 1942, even though they were in possession of the German plans. On 19 June, the chief of operations of the 23rd Panzer Division, Major Joachim Reichel, was shot down over Soviet-held territory while flying an observation aircraft over the front near Kharkov. The Soviets recovered maps from his aircraft detailing the exact German plans for Case Blue. The plans were handed over to Stavka, in Moscow.
Joseph Stalin, however, believing it to be a German ruse, remained convinced that the primary German strategic goal in 1942 would be Moscow, in part due to Operation Kremlin (Fall Kreml), a German deception plan aimed at the city. As a result, the majority of Red Army troops were deployed there, although the direction from which the Case Blue offensive would come was still defended by the Bryansk, Southwestern, Southern and North Caucasian Fronts. With about 1 million soldiers at the front line and another 1.7 million in reserve armies, their forces accounted for about one quarter of all Soviet troops. Following the disastrous start of Case Blue for the Soviets, they reorganized their frontlines several times. Over the course of the campaign, the Soviets also fielded the Voronezh Front, Don Front, Stalingrad Front, Transcaucasian Front, and the Caucasian Front, though not all existed at the same time.
With the German thrust expected in the north, Stavka planned several local offensives in the south to weaken the Germans. The most important of these was aimed at the city of Kharkov and would be conducted mainly by the Southwestern Front under Semyon Timoshenko, supported by the Southern Front commanded by Rodion Malinovsky. The operation was scheduled for 12 May, just prior to a planned German offensive in the area. The ensuing Second Battle of Kharkov ended in disaster for the Soviets, severely weakening their mobile forces. At the same time, the Axis clearing of the Kerch Peninsula together with the Battle of Sevastopol, which lasted until July, weakened the Soviets further and allowed the Germans to supply Army Group A across the Kerch Peninsula through the Kuban.
The Red Army order of battle at the start of the campaign was as follows:
Northern Sector (Volga campaign)
Armies deployed north to south:
The offensive
Opening phase
The German offensive commenced on 28 June 1942, with Fourth Panzer Army starting its drive towards Voronezh. Due to a chaotic Soviet retreat, the Germans were able to advance rapidly, restoring Wehrmacht confidence for the upcoming major offensive.
Close air support from the Luftwaffe also played an important role in this early success. It contained the Red Air Force, through air superiority operations, and provided interdiction through attacks on airfields and Soviet defence lines. At times, the German air arm acted as a spearhead rather than a support force, ranging on ahead of the tanks and infantry to disrupt and destroy defensive positions. As many as 100 German aircraft were concentrated on a single Soviet division in the path of the spearhead during this phase. General Kazakov, the Bryansk Front's chief of staff, noted the strength and effectiveness of the Axis aviation. Within 26 days, the Soviets lost 783 aircraft from the 2nd, 4th, 5th and 8th Air Armies, compared to a German total of 175.
By 5 July, forward elements of Fourth Panzer Army had reached the Don River near Voronezh and became embroiled in the battle to capture the city. Stalin and the Soviet command still expected the main German thrust in the north against Moscow, and believed the Germans would turn north after Voronezh to threaten the capital. As a result, the Soviets rushed reinforcements into the town to hold it at all costs and counterattacked the Germans' northern flank in an effort to cut off the German spearheads. 5th Tank Army, commanded by Major General A.I. Liziukov, managed to achieve some minor successes when it began its attack on 6 July, but was forced back to its starting positions by 15 July, losing about half of its tanks in the process. Although the battle was a success, Hitler and Fedor von Bock, commander of Army Group South, argued over the next steps in the operation. The heated debate, and continuing Soviet counterattacks, which tied down Fourth Panzer Army until 13 July, caused Hitler to lose his temper and dismiss Bock on 17 July. As part of the second phase of the operation, on 9 July, Army Group South was split into Army Group A and Army Group B, with Wilhelm List appointed as commander of Army Group A and Army Group B commanded by Maximillian von Weichs.
Only two weeks into the operation, on 11 July, the Germans began to suffer logistical difficulties, which slowed the advance. The German Sixth Army was continually delayed by fuel shortages. Eight days later, on 20 July, shortages of fuel were still undermining operations, leaving many units unable to execute their orders. The 23rd Panzer Division and 24th Panzer Division both became stranded during the opening phase. Once again, as it had done during the Norwegian Campaign in April 1940, and Barbarossa in 1941, the Luftwaffe's Junkers Ju 52 transport fleet flew in supplies to keep the army going. The situation remained difficult with German troops forced to recover fuel from damaged or abandoned vehicles, and in some cases, leave behind tanks and vehicles with heavy fuel consumption to continue their advance. This undermined the strength of the units, which were forced to leave fighting vehicles behind. Nevertheless, the Luftwaffe flew in 200 tons of fuel per day to keep the army supplied. Despite this impressive performance in keeping the army mobile, Löhr was replaced by the more impetuous and offensive-minded Richthofen.
Splitting of Army Group South
Believing that the main Soviet threat had been eliminated, desperately short of oil and needing to meet all the ambitious objectives of Case Blue, Hitler made a series of changes to the plan in Führer Directive No. 45 on July 23, 1942: