Moscow, Russian Confederation.
The Russian Confederation is a successor state to the former Russian Empire, emerging from five years of civil war after the collapse of the Empire in the Russian Revolution of 1900. Although Sobel does not state what part of the former empire it covers, it most likely includes the original Russian capital of Moscow.
The Russian Confederation was involved in a second round of wars with the other successor states between 1947 and 1955 known as the Time of Troubles, most likely in response to the Japanese invasion of Siberia. The Russian Confederation joined with other German-allied Russian successor states to form the Associated Russian Republics on 20 November 1965, and the Germans detonated their first Atomic bomb at a remote testing area in the eastern reaches of the Russian Confederation on 19 March 1966. Growing anti-German sentiment in the Russian Confederation led to the outbreak of rioting in Moscow in 1969.