Operation Case Blue
Case Blue (German: Fall Blau), later named Operation Braunschweig, was the German Armed Forces’ (Wehrmacht) name for its plan for the 1942 strategic summer offensive in southern Russia between 28 June and 24 November 1942, during World War II.
The operation was a continuation of the previous year’s Operation Barbarossa, intended to knock the Soviet Union out of the war. It 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 in the direction of Stalingrad along the Volga River, known as Operation Fischreiher.
Army Group South (Heeresgruppe Süd) of the German Army was divided into Army Groups A and B (Heeresgruppe A and B). Army Group A was tasked with crossing the Caucasus mountains to reach the Baku oil fields, while Army Group B protected its flanks along the Volga. Supported by 2,035 Luftwaffe aircraft and 1,934 tanks and assault guns, the 1,370,287-man Army Group South attacked on 28 June, advancing 48 kilometers on the first day and easily brushing aside the 1,715,000 Red Army troops opposite, who falsely 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 newly deployed Red Army reserves and overstretched German supply lines. The Germans defeated the Soviets in the Battle of Kalach and the combat shifted to the city itself in late August. Nonstop Luftwaffe airstrikes, artillery fire and street-to-street combat completely destroyed the city and inflicted heavy casualties on the opposing forces. After three months of battle, the Germans controlled 90% of Stalingrad on 19 November.
In the south, Army Group A captured Rostov 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. Heavy 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 Caucasus oilfield at Baku. Luftwaffe bombers destroyed the oilfields at Grozny but attacks on Baku were prevented by the insufficient range of the German fighters.
The possibility that the Germans would continue to the south and east, and possibly link up with Japanese forces (then advancing in Burma) in India, was of great concern to the Allies. However, the Red Army defeated the Germans at Stalingrad, following Operations Uranus and Little Saturn. This defeat forced the Axis to retreat from the Caucasus. Only the Kuban region remained tentatively occupied by Axis troops.