舞鶴鎮守府
In February 1925, Hyakutake was sent as a naval attache to France and in June of the same year was part of Japan's delegation to the League of Nations. In December 1925, while in France, he was promoted to rear admiral, and returned to Japan in February 1926. On his return, he continued to teach at the Naval Staff College, continuing to promote the concepts of disarmament, external cooperation and negotiations and thus coming increasingly into conflict with the militaristic ultra-nationalism of General Sadao Araki and members of the Imperial Japanese Army's Imperial Way Faction. His relations with General Shigeru Honjō were so strained that Honjō refused to speak or meet with him. Hyakutake was promoted to vice admiral on December 1, 1930, and became Commandant of the Naval Staff College in 1932. In September 1933, he was transferred to become commander of the Maizuru Naval District and in November 1934 was commander-in-chief of the IJN 3rd Fleet. He became commander of the Sasebo Naval District in December 1935 and commander of the Yokosuka Naval District from December 1936. Promoted to full admiral on April 1, 1937, Hyakutake then became a Naval Councillor on April 26, 1938. He remained stubbornly steadfast in his opposition to war with the United States, and was forced into early retirement in July 1942. In March 1945, he briefly was president of Kyushu Imperial University.