The overthrow of Tsar Nicholas II and the establishment of a Bolshevik government in Russia led to a separate peace with Germany and the collapse of the Eastern Front.

After an armed mob looted a Japanese-owned store, killing its owner, the Japanese government, without waiting for an investigation of the murder, permitted the landing of marines, who proceeded to occupy the entire city.

[citation needed] Once the political decision had been reached, the Imperial Japanese Army took over full control under Chief of Staff Yui Mitsue and extensive planning for the expedition was conducted.

On June 24, 1922, Japan announced that it would unilaterally withdraw from all of Russian territory by October, with the exception of northern Sakhalin island, which had been seized in retaliation for the Nikolayevsk incident of 1920.

Overtly, Japan (as with the United States and the other international coalition forces) was in Siberia to safeguard stockpiled military supplies and to rescue the Czechoslovak Legion.

However, the Japanese government's antipathy to communism and socialism, a determination to recoup historical losses to Russia, and the perceived opportunity to settle the "northern problem" to Japan's advantage by either creating a buffer state[6] or through outright territorial acquisition were also factors.

However, patronage of various White Movement leaders left Japan in a poor diplomatic position vis-à-vis the government of the Soviet Union, after the Red Army eventually emerged victorious from the Russian Civil War.

[6] The official conduct of the Siberian Intervention was later bitterly attacked in the Japanese Diet, with the Army being accused of grossly misrepresenting the size of the forces sent, misappropriating secret funds, and supporting figures such as lieutenant general Roman von Ungern-Sternberg, rumors of whose atrocities had reached the press.