Political map of Russia & the former Soviet Union 19 May 1920 (Creation of the Far Eastern Republic): On the night of April 4-5, Japanese retaliated for the Nikolayevsk Incident (Nikolaevsk Incident) by assaulting Russian partisan positions in the Far East and installing a new government in Vladivostok. In response, the Russians declared a Far Eastern Republic (Far Eastern Republic) at Verkhneudinsk. Nominally an independent state, it served as a buffer between Japan and Russia over the next few years.