Ships
- IJN Hosho Captain from 15 November 1942 · Relieved on 5 July 1943
Katsuji Hattori was a career officer of the Imperial Japanese Navy, a graduate of the 44th class of the Naval Academy, and a gunnery specialist who later moved into aviation. He commanded the aircraft carrier Hosho as a captain in 1942 and 1943 and rose to rear admiral before the end of the war.
On 1 April 1930 he returned to the Naval Academy as an instructor and supervisor. In November 1932 he became gunnery officer of the heavy cruiser Kako, and the following month he also served as a division officer. After a short attachment to the First Fleet in the autumn of 1933, he was gunnery officer of the battleship Kongo from 15 November 1933. From 22 October 1934 he was executive officer of the light cruiser Isuzu. He taught at the gunnery school from October 1935, and in December 1936 he joined the staff of the Yokosuka guard squadron.
In December 1937 he was attached to fleet staffs, including the Second Fleet. In June 1938 he went to the Kasumigaura Air Group as an instructor, and on 15 November 1938 he took command of the Omura Air Group. On 15 November 1939 he became captain of the seaplane carrier Kamoi. On 15 November 1940 he moved to the seaplane tender Kamikawa Maru, and on 20 September 1941 he left her to command the Hakata Air Group, the shore post he still held when the Pacific War began.
Hosho, completed in December 1922, was the first aircraft carrier the Imperial Navy built as such from the keel up. She had served off China and, in June 1942, had gone to sea with the battleships of the Main Body for the Midway operation, her small group of older aircraft used for scouting and patrol. After that cruise she was docked and fitted for training. By the autumn of 1942 she belonged to the carrier-training organization and worked up new aircrews in deck landings, with the destroyer Yukaze as guard ship.
Hattori became captain of Hosho on 15 November 1942, in succession to Captain Bunjiro Yamaguchi. On 15 January 1943 the ship joined the third section of the Mobile Force training organization, under the 50th Air Flotilla of the Third Fleet, and operated in the western Inland Sea. Through the months of his command her flight deck was a school for carrier landings. He was relieved on 5 July 1943 by Captain Takeo Kaizuka, and the same day he was appointed captain of the light carrier Zuiho.
He stood in a line of captains that reached back to the ship's first years. Jiro Toshima had charge of Hosho as she finished fitting out and entered service. Heizaburo Fukuyo commanded her through most of 1923, and Ryutaro Kaizu followed from December 1923 into 1925, while the navy was still learning how to operate aircraft from a flight deck at sea.
In February 1944 Hattori was assigned to the Suzuka Air Group, and from 30 April 1944 he was its commanding officer. He was promoted rear admiral on 1 May 1944. He commanded the Yokosuka Air Group from 10 July 1944, then the 19th Combined Air Group from 29 September 1944. On 1 March 1945 he became commander of the naval barracks at Ominato, and from 10 July 1945 he also commanded the Ominato Combined Special Naval Landing Force. He held both posts until he was transferred to the reserve on 15 November 1945.