https://en.wikipedia.org/wiki/Japanese_intervention_in_Siberia In the aftermath of WW1 during the Russian Civil War the Japanese intervened in the Russian Far East/Siberia deploying up to 70K troops. They established effective control over a decent piece of territory including Vladivostok and North Salakhin and Japanese troops ventured as far west as Lake Baikal. So my challenge is can Japan realistically maintain control or even formally annex parts of the former Russian empire as a result of the intervention. At a minimum this would mean some border territories, Vladivostok and Northern Salakhin. The maximum would be say a slice of territory stretching to Lake Baikal. Is this possible? If so would Japan control this territory as a puppet state like Manchukoko or formally annex it like Formosa and Korea? Or perhaps some combination of both. What would the economic and military effects of this be for Japan and for the Soviet Union (assuming it exists). What are the social effects from a much more sizable White Russian population in the Japanese empire? How can the diplomatic situation be worked out enough to achieve at the least American and British acceptance of this?