It seems some forgot that the Japanese once controlled Vladivostok. Even though they were technically propping up a White Russian leader in Vladivostok. They could have taken controlled. When the other allies left in April 1920 the Japanese Troops were the only foreign troops in Vladivostok. Japanese left Oct. 1922.
This Photo is when they got there in 1918:
Japanese Troops at the docks of Vladivostok:
Japanese got to Vladivostok around August 18, 1918. They left in 1922. But they did control Northern Sakhalin island from 1921 to 1925. They signed an agreement with the Soviets at the Beijing convention on January 20 1925 to return to the Soviets Northern Sakhalin.
When the Japanese got involved in Siberia the Japanese Prime Minister Terauchi Masatake and some in his government did not want to really get involved in Russia. While others in the government and military did want to get involved. So the Japanese government was split. They did get involved after the US asked them to send troops to Siberia to help prop up the White Russians. Other nations also sent troops. Italy sent troops as well as the UK.. Even China sent troops. Japanese sent 12000.
This is a time line I found:
1918
1/12 Japanese and British navies sent warships to Vladivostok
4/5 Japanese and British naval landing forces landed at Vladivostok
8/12 Japanese army landed at Vladivostok
9/6 The Japanese occupied Chita
9/22 The whole Amour Railway was occupied by intervention armies
1919
2/25 Tanaka Detachment was annihilated by Soviet partisan
11/14 Omsk was occupied by Red Army
1920
1/9 USA declared the retreat from Siberia
2/24 UK declared the retreat from Siberia
4/4 The Japanese occupied Vladivostok
4/6 Far-East Republic was established at Chita
5/25 Japanese garrisons and civilians at Nikolaevsk were slaugtered by Soviet partisan
8/20 The Japanese retreated from Zabaikal
9/2 Czech troops escape from Russia
12/12 The Japanese retreated from Khabarovsk
1922
6/24 Japanese Government declared the retreat from Siberia
10/25 All Japanese forces retreated from Siberia
Should be noted that the Allies sent troops to Russian Far East to make sure the Germans did not get all the weapons that had been sent via the Far Eastern Russia. Also, to try to help get the 50000 Czechs that were trapped in Russia out of there and back into the fight in Europe. And to try to help prop up the White Russians.
It seems the weather plus Soviet determination made them change there minds. Even the Japanese left.
Photo of Japanese with captured Soviet Armor truck:
Photo of Japanese leaving Vladivostok in Oct. 1922.
Map of Japanese Campaign in Far Eastern Russia: