 Complete the following phrase:  Okabe was born in Hiroshima city and attended military preparatory schools as a youth. He graduated from the 18th class of the Imperial Japanese Army Academy, where his classmates included Tomoyuki Yamashita and Korechika Anami. He subsequently graduated from the 27th class of the Army Staff College. In 1918, with the rank of captain, he was sent to the Vladivostok Special Operations Office during the 