When did the Siberian Intervention begin?

The Siberian Intervention or Siberian Expedition of 1918–1922 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 and China to support White Russian forces against Soviet Russia and its allies during the Russian Civil War.

The Imperial Japanese Army continued to occupy Siberia even after other Allied forces withdrew in 1920.