The Pak 36 is a 3.7 cm / 37mm caliber German anti-tank gun used during the Second World War. It was the main anti-tank weapon of Wehrmacht Panzerjäger units until 1942. Developed by Rheinmetall in 1933, it was first issued to the German Army in 1936, with 9,120 being available by the beginning of the war in September 1939 and a further 5,339 produced during the war. As the predominant anti-tank gun design in the world during the late 1930s, demand was high for the Pak 36, with another 6,000 examples produced for export and the design being copied by the Soviet Union as the 45 mm anti-tank gun M1932 (19-K) and by other nations such as Japan.

Operation Uranus was the codename of the Soviet Red Army's 19–23 November 1942 strategic operation on the Eastern Front of World War II which led to the encirclement of Axis forces in the vicinity of Stalingrad: the German Sixth Army, the Third and Fourth Romanian armies, and portions of the German Fourth Panzer Army. The Red Army carried out the operation at roughly the midpoint of the five-month long Battle of Stalingrad, aiming to destroy German forces in and around Stalingrad. Planning for Operation Uranus had commenced in September 1942, and developed simultaneously with plans to envelop and destroy German Army Group Center and German forces in the Caucasus.