Siberian Intervention The , or the 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 to support White Russian forces against the Bolshevik Red Army during the Russian Civil War . The Imperial Japanese Army continued to occupy Siberia even after other Allied forces had withdrawn in 1920 . Background . Following the Russian October Revolution of 1917 , the new Bolshevik government signed a separate peace with Germany . The collapse of the Russian front presented a tremendous problem to the Entente powers , since not only did it allow Germany to shift troops and war material from its eastern front to the west , but it also made it possible for Germany to secure the huge stockpiles of supplies that had been accumulating at Murmansk , Arkhangelsk and Vladivostok . In addition , the 50 , 000 man Czechoslovak Legion , fighting on the side of the Allies , was now behind enemy lines , and was attempting to fight its way out through the east to Vladivostok along the Bolshevik - held Trans - Siberian Railway . Faced with these concerns , Great Britain and France decided to militarily intervene in the Russian Civil War against the Bolshevik government . They had three objectives that they hoped to achieve : Severely short of troops , the British and French requested that the United States provide troops for both the North Russia Campaign and the Siberian Campaign . In July 1918 , against the advice of the United States Department of War , President Wilson agreed to send 5 , 000 US troops as the American North Russia Expeditionary Force ( aka the Polar Bear Expedition ) and 10 , 000 US troops as the American Expeditionary Force Siberia . In the same month , the Beiyang government of the Republic of China accepted an invitation by the Chinese community in Russia and sent 2 , 000 troops by August . The Chinese later occupied Outer Mongolia and Tuva and sent a battalion to the North Russian Campaign as part of their anti - Bolshevik efforts . Participants . Britain . The British , short on personnel , only deployed 1 , 500 troops to Siberia . These men came from the 9th Battalion , Hampshire Regiment and the 25th Battalion , Middlesex Regiment . Canada . The Canadian Siberian Expeditionary Force , commanded by Major General James H . Elmsley and authorised in August 1918 , was sent to Vladivostok to bolster the allied presence there . Composed of 4 , 192 soldiers , the force returned to Canada between April and June 1919 . During this time , the Canadians saw little fighting , with fewer than 100 troops proceeding " up country " to Omsk , to serve as administrative staff for 1 , 500 British troops aiding the White Russian government of Admiral Alexander Kolchak . Most Canadians remained in Vladivostok , undertaking routine drill and policing duties in the volatile port city . Italy . The " Corpo di Spedizione Italiano in Estremo Oriente " was made of Alpini troops , supported by 2 , 500 ex - Italian POWs , who had fought in the Austro - Hungarian Army , enrolled in the Legione Redenta . The Italians played a small but important role during the intervention , fighting together with the Czechoslovak Legion and other allied forces using heavily armed and armoured train s to control large sections of the Siberian railway . The main areas of operation were the Irkutsk , Harbin and Vladivostok regions . Japan . The Japanese were initially asked by the French in 1917 , to intervene in Russia but declined the request . However , the army general staff later came to view the Tsarist collapse as an opportunity to free Japan from any future threat from Russia by detaching Siberia and forming an independent buffer state . The Japanese government in the beginning refused to undertake such an expedition and it was not until the following year that events were set in motion that led to a change in this policy . In July 1918 , President Wilson asked the Japanese government to supply 7 , 000 troops as part of an international coalition of 25 , 000 troops , including an American expeditionary force , planned to support the rescue of the Czechoslovak Legions and recurring of wartime supplies . After heated debate in the Diet , the administration of Prime Minister Terauchi Masatake agreed to send 12 , 000 troops , but under the command of Japan , rather than as part of an international coalition . 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 . United States . The American Expeditionary Force Siberia was commanded by Major General William S . Graves and eventually totaled 7 , 950 officers and enlisted men . The AEF Siberia included the U . S . Army ' s 27th and 31st Infantry Regiments , plus large numbers of volunteers from the 13th and 62nd Infantry Regiments along with a few from the 12th Infantry Regiment . Although General Graves did not arrive in Siberia until September 4 , 1918 , the first 3 , 000 American troops disembarked in Vladivostok between August 15 and August 21 , 1918 . They were quickly assigned guard duty along segments of the railway between Vladivostok and Nikolsk - Ussuriski in the north . Unlike his Allied counterparts , General Graves believed their mission in Siberia was to provide protection for American - supplied property and to help the Czechoslovak Legions evacuate Russia , and that it did not include fighting against the Bolsheviks . Repeatedly calling for restraint , Graves often clashed with commanders of British , French and Japan ese forces , who wanted the Americans to take a more active part in the military intervention in Siberia . Allied intervention ( 1918 – 1919 ) . The joint Allied intervention began in August 1918 . The Japanese entered through Vladivostok and points along the Manchurian border with more than 70 , 000 Japanese troops being involved . The deployment of a large force for a rescue expedition made the Allies wary of Japanese intentions . On September 5 , the Japanese linked up with the vanguard of the Czechoslovak Legion . A few days later the British , Italian and French contingents joined the Czechs and Slovaks in an effort to re - establish the east Front beyond the Urals ; as a result the European allies trekked westwards . The Japanese , with their own objectives in mind , refused to proceed west of Lake Baikal and stayed behind . The Americans , suspicious of Japanese intentions , also stayed behind to keep an eye on the Japanese . By November , the Japanese occupied all ports and major towns in the Russian Maritime Provinces and in Siberia east of the city of Chita . In the summer of 1918 onwards , the Japanese army lent its support to White Russian elements ; the 5th infantry division and the Japanese - backed Special Manchurian Detachment of Grigory Semyonov took control over Transbaikalia and founded a short - lived White Transbaikalia government . Allied withdrawal ( 1919 – 1920 ) . With the end of the war in Europe the allies decided to support the anti - Bolshevik White forces and effectively intervene in the Russian Civil War . Allied army support was given to Admiral Kolchak ' s White government at Omsk while the Japanese continued to support Kolchak ' s rivals in Grigory Semyonov and Ivan Kalmykov . In the Summer of 1919 , the White regime in Siberia collapsed , after the capture and execution of Admiral Kolchak by the Red Army . In June 1920 , the Americans , British and the remaining allied coalition partners withdrew from Vladivostok . The evacuation of the Czechoslovak Legion was also carried out in the same year . However , the Japanese decided to stay , primarily due to fears of the spread of communism so close to Japan , and the Japanese controlled Korea and Manchuria . The Japanese were forced to sign the Gongota Agreement of 1920 in order to evacuate their troops peacefully from Transbaikal . It meant an unavoidable end to Grigory Semyonov ' s regime in October 1920 . The Japanese army provided military support to the Japanese - backed Provisional Priamur Government based in Vladivostok against the Moscow - backed Far Eastern Republic . The continued Japanese presence concerned the United States , which suspected that Japan had territorial designs on Siberia and the Russian Far East . Subjected to intense diplomatic pressure by the United States and Great Britain , and facing increasing domestic opposition due to the economic and human cost , the administration of Prime Minister Kato Tomosaburo withdrew the Japanese forces in October 1922 . Legacy . Effects on Japanese politics . Japan ' s motives in the Siberian Intervention were complex and poorly articulated . 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 intense hostility to communism , a determination to recoup historical losses to Russia , and the perceived opportunity to settle the " northern problem " in Japan ' s security by either creating a buffer state , 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 . The intervention tore Japan ' s wartime unity to shreds , leading to the army and government being involved in bitter controversy and renewed faction strife in the army itself . Japanese casualties from the Siberian Expedition included some 5 , 000 dead from combat or illness , and the expenses incurred were in excess of 900 million yen .