Political map of Russia & the former Soviet Union 3 April 1920 (Nikolayevsk Incident): In January and February, communist partisans and their supporters overthrew the whites across the Russian Far East. However, this was a region that had fallen under Japanese military influence during the Allied Intervention (Japan during the Siberian Intervention). Initially the outnumbered Japanese garrisons accepted the new situation, but soon tensions led to conflict. On March 12, Japanese troops in Nikolayevsk attempted a surprise attack (Nikolaevsk Incident). The attack failed and a general massacre of the Japanese (Nikolaevsk Incident) in the city ensued.