It was essentially a home guard and garrison, responsible for recruitment and civil defense training to ensure the security of Tokyo, Yokohama, and the surrounding areas.
The Eastern District Army played an especially significant role in combating the 15 August 1945 attempted coup d'etat of Major Kenji Hatanaka, who sought to prevent the Emperor's announcement of Japan's surrender from being broadcast.
At the time, the commander of the Eastern District Army was Lieutenant General Shizuichi Tanaka.
Tanaka refused, and later told his men to ignore Strategic Order 584, forged by Hatanaka and ordering the Eastern District Army to seize and defend the Imperial Palace; in short, to aid in the coup.
The Eastern District Army remained active for several months after the surrender of Japan to help maintain public order until the arrival of the American occupation forces, and to oversee the final demobilization and dissolution of the Imperial Japanese Army.