The Sakurakai was led by Imperial Japanese Army Lieutenant Colonel Kingoro Hashimoto, then chief of the Russian section of the Imperial Japanese Army General Staff and Captain Isamu Cho with the support of Sadao Araki. The society began with about ten members, active-duty field grade officers of the Army General Staff, and expanded to include regimental-grade and company-grade officers, so that its membership increased to more than 50 by February 1931, and possibly up to several hundred by October 1931. One prominent leader was Kuniaki Koiso, future Prime Minister of Japan.