At the age of 33, Captain Yasue was assigned as part of the Japanese intervention in Siberia, to aid the Russian White Army in their struggle against the Bolshevik Red Army. A Russian-language specialist, he was assigned to the staff of General Gregorii Semenov, a vehement anti-Semite who distributed copies of the "Protocols of the Elders of Zion" to all of his troops, along with weapons and rations. Along with a few dozen other Japanese soldiers, Yasue read and accepted the premises of the "Protocols", and would allow this to guide much of his actions and views into the time of the beginning of World War II.