Ships
- IJN Yamashiro Captain from 24 May 1941
Chozaemon Obata was born on 10 December 1893 and spent his career in the Imperial Japanese Navy as a gunnery officer. As a junior officer he served in Ise, held secondary-battery duty in Hiei, and was gunnery officer of the light cruiser Yura. He was promoted to lieutenant commander in December 1927. He then served as gunnery officer of the heavy cruiser Nachi and of the battleship Kongo, and he was promoted to commander in December 1932. Through the middle of the 1930s he instructed in gunnery.
He reached the rank of captain in December 1936. In September 1937 he became special-service captain of the auxiliary Suzaki. The following year he went ashore as a staff officer of the Sasebo Naval District, with additional duty on the staff of the Nagasaki Fortress. On 15 April 1940 he took command of the minelayer Okinoshima. On 15 October 1940 he moved to the heavy cruiser Kumano. He left Kumano to become captain of the battleship Yamashiro on 24 May 1941.
Yamashiro was assigned to Battleship Division 2 of the First Fleet, with Fuso, Ise, and Hyuga, under Vice Admiral Shiro Takasu. From 8 August until 1 October 1941 Obata was also captain of Kenzaki while he remained in Yamashiro. When the Pacific War opened, the division, reinforced by Nagato, Mutsu, and the light carrier Hosho, left the Hashirajima anchorage and steamed toward the Bonin Islands as distant cover for the carrier attack on Pearl Harbor. The ships returned to home waters within a few days, and Yamashiro settled into standby duty in the Inland Sea.
After American bombers struck Tokyo in April 1942, Yamashiro sortied in search of the raiding force and came back several days later, the search having ended without contact. Late in May she sailed with the rest of Battleship Division 2 in the force sent to support the Aleutian operation, which went forward at the same time as the attack on Midway, and that cruise also ended without a meeting. She spent the summer at Hashirajima on training and alert duty. In July the First Fleet was reorganized and Nagato and Mutsu joined the division. Near the end of August Yamashiro entered dry dock at Kure.
Captain Noboru Owada relieved him on 1 September 1942. Obata went to Hong Kong as commander of the Hong Kong Area Special Base Force and, in the same appointment, chief of staff of the Second China Expeditionary Fleet. He was promoted to rear admiral on 1 November 1942 and remained in those duties into the autumn of 1943.
On 19 October 1943 he was attached to the Yokosuka Naval District, and on 1 November he became head of the Yokosuka Gunnery School. He was still in that post at the surrender. He was placed on the reserve list on 25 October 1945 and died on 18 December 1948.
Yamashiro stayed in home waters long after Obata left her. Yoshioki Tawara later commanded the ship and died of illness in May 1944 while still her captain. That October she wore the flag of Vice Admiral Shoji Nishimura and, with Katsukiyo Shinoda as captain, went into Surigao Strait with the southern force. She was sunk in the night battle of 25 October 1944, and Nishimura and Shinoda were lost with her.