The Siberian Intervention ( 1918-1922 ) was part of a larger plan by the Western powers and Japan . They wanted to support the White Russians against the Bolshevik Red Army during the Russian Civil War . The Siberian Intervention of 1918 â `` 1922 was the dispatch of troops of the Entente powers to the Russian Maritime Provinces as part of a larger effort by the western powers and Japan to support White Russian forces against the Bolshevik Red Army during the Russian Civil War .