Tanabe was from Ishikawa prefecture, where his father was a former samurai of Kaga Domain and later a colonel in the early Imperial Japanese Army.

This was also a new organization, raised in Yongsan District, Korea, and was assigned to 1st Army as a garrison force in Japanese-occupied Shanxi Province.

Tanabe was recalled to Japan at the end of 1941 to serve as Vice Chief of the Imperial Japanese Army General Staff, and was in this position at the time of the attack on Pearl Harbor, which he had strenuously opposed.

Once the war began, he favored a defensive strategy of luring the Allies into campaigns in areas away from their bases in hopes of stretching their supply lines to Japan's advantage.

[4] Tanabe had reservations about the increasing role of the Indonesian nationalist movement on Java, but responding to the “Koiso Promise” granting increased autonomy and eventual independence to Indonesia he established the Sumatra Central Advisory Committee and trained locals for administrative leadership roles.