Italian Eighth Army from early August) Case Blue (German: Fall Blau) was the Wehrmacht's plan for the 1942 strategic summer offensive in southern Russia between 28 June and 24 November 1942, during World War II.

Nonstop Luftwaffe airstrikes, artillery fire and street-to-street combat completely destroyed the city and inflicted heavy casualties on the opposing forces.

[8][9] On 22 June 1941, Germany launched Operation Barbarossa with the intention of defeating the Soviet Union in a quick offensive which was expected to last only 3 months.

[10] By February 1942 the German Army High Command (OKH) had begun to develop plans for a follow-up campaign to the aborted Barbarossa offensive – with the Caucasus as its principal objective.

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.

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.

[17] The offensive was to be conducted across the southern Russian (Kuban) steppe utilizing the following Army Group units:[20] Northern Sector (Volga campaign)[21] Southern Sector (Caucasus campaign) 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.

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.

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.

[32] 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.

[35] 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.

Logistics lines were already at breaking point with ammunition and fuel shortages most apparent and it would be impossible to advance using the conservative supply rates he demanded.

[42] After crossing the Don on 25 July, Army Group A fanned out on a 200 km (120 mi) front from the Sea of Azov to Zymlianskaya (today Zymlyansk).

On 29 July the Germans cut the last direct railway between central Russia and the Caucasus, causing considerable panic to Stalin and Stavka, which led to the passing of Order No.

[45] The length of the German advance created chronic supply difficulties, particularly of petrol; the Black Sea was judged too dangerous and fuel was brought by rail through Rostov or delivered by air, but panzer divisions were sometimes at a standstill for weeks.

[55] German mountain troops failed to secure the Black Sea ports and the advance fell short of Grozny as supply difficulties arose once more.

[56] At the beginning of September, Hitler had a major argument with the High Command and specifically List, as he perceived the advance of the German forces as too slow.

[citation needed] On 2 November 1942, Romanian mountain troops (Vânători de munte) under the command of Brigadier General Ioan Dumitrache took Nalchik, the capital of Kabardino-Balkaria and also the farthest point of Axis advance into the Caucasus.

Only the German 16th Motorized Infantry Division remained inside the gap, guarding the left flank of the First Panzer Army by securing the road towards Astrakhan.

[68] On 22 November, after several Soviet counter-attacks, Hitler appointed Kleist as Group commander with orders to hold his position and prepare to resume the offensive if Stalingrad could be taken.

In the first week of October 1942, Hitler came to recognize that the capture of the Caucasus oil fields was unlikely before winter, which forced the Germans to take up defensive positions.

On 19 November, the Soviet counter-offensive at Stalingrad compelled Richthofen to once more withdraw his units north to the Volga and bring an end to the aerial offensive.

On 26 July, XIV Panzer Corps broke through and reached the Don, where the new First and Fourth Tank Armies conducted several futile counter-attacks by inexperienced troops.

[74] The Soviet defence at the Don forced the Germans to commit more and more troops to an increasingly vulnerable front, leaving few reserves to back up the Axis divisions on either flank.

Anticipating victory, substantial numbers of Luftwaffe aircraft were withdrawn to the Mediterranean in early November to support the Axis operations in Tunisia.

The operations continued until January and led Stavka to believe that they could deal a fatal blow to the Germans and decide the war in southern Russia.

[45] Hitler did not expect the Soviets to be able to launch a counter-offensive as big as Operation Uranus and sent troops elsewhere, ordering the Wehrmacht to simultaneously achieve several goals.

f Surrendered remains of Sixth Army at Stalingrad 31 January 1943. g A set of plans for Fall Blau held by an officer of one of Stumme's panzer divisions fell into Soviet hands on 19 June.

h Captured at Stalingrad 31 January 1943, died in captivity 9 February 1944. i Executed by firing squad for war crimes November 1947. j Committed suicide October 1944 following arrest by the Gestapo.