Ships
- IJN Nagato Captain from 10 November 1942
Yonejiro Hisamune was born on 15 February 1892 and was trained for the Imperial Japanese Navy at the Naval Academy. He graduated on 19 December 1913, sixty-fifth in a class of 118, and began as a midshipman in the armored cruiser Asama. In August 1914 he moved to the battleship Aki, and he was commissioned ensign on 1 December 1914. Duty in the battleship Iwami followed. On 1 December 1916 he became a lieutenant junior grade and entered the torpedo branch, completing the basic torpedo course and the basic gunnery course before joining the destroyer Asagiri at the end of 1917.
Destroyers and torpedo work filled the next twenty years. Promoted lieutenant on 1 December 1920, he finished the specialist torpedo course and served in Momi, Urakaze, and a destroyer carried on the list as D-6. From December 1924 he was an instructor at the Torpedo School. On 1 December 1926 he was made a lieutenant commander and given the destroyer Kaya, then Fuyo, Kamikaze, and Yukaze. As a commander from 1 December 1932 he had Yugiri, Hatsuyuki, and Uranami. In October 1935 he took Destroyer Division 14, shifted to Destroyer Division 29 a year later, and on 31 May 1937 took Destroyer Division 24. During the fighting in China that division spent the autumn of 1937 on aircraft-guard and escort duty, covering bomber operations around Canton and afterward in Hangzhou Bay and the country inland toward Suzhou and Wuxi.
Hisamune was promoted captain on 15 November 1938. His first command in that rank was the submarine tender Chogei, from 15 December 1938. After a short attachment to the Kure Naval District in the spring of 1939, he led Destroyer Division 18 from July and, from 15 November 1939, the light cruiser Sendai. On 25 July 1941 he took the heavy cruiser Aoba of the Sixth Squadron. In the first year of the Pacific War that squadron covered early landing operations, the Port Moresby movement in the Coral Sea, and the night battle off Savo Island in August 1942. On the night of 11–12 October 1942, off Cape Esperance, Aoba was badly hit and the squadron commander, Rear Admiral Aritomo Goto, was mortally wounded. Hisamune stayed with the cruiser until he was ordered to a battleship.
On 10 November 1942 he became captain of the battleship Nagato. Earlier in the war the ship had been the Combined Fleet flagship of Isoroku Yamamoto, and after that flag moved to Yamato she had passed through the Midway operation and joined Battleship Division 2. Under Hisamune she remained in home waters on training duty, exercising from the Inland Sea anchorages while the fleet's fighting ships were pushed farther south.
On 8 June 1943 the routine ended at Hashirajima. Nagato was underway nearby when the battleship Mutsu exploded and sank. Aboard Nagato the blast was first taken for gunnery practice. A report from Fuso then said that Mutsu was gone, and the explosion was read as a submarine attack. Hisamune increased speed to clear the scene and shaped a course for Kure, while a boat was sent toward the wreck. Vice Admiral Mitsumi Shimizu, commanding the First Fleet, ordered Nagato back to the Hashirajima anchorage, and the battleship turned to the rescue.
On 2 August 1943 he turned Nagato over to Mikio Hayakawa and took command of the battleship Yamashiro. He was promoted rear admiral on 1 November 1943, still in that ship, and on 25 December 1943 he left her to command Cruiser Division 22. Yamashiro was still employed on training service in home waters at the time he departed.
In the last winter of the war he was moved into the escort force. He joined the staff of the First Escort Fleet on 21 December 1944, took the Fifth Convoy Headquarters on 25 December, and on 20 January 1945 became commander of the 103rd Escort Squadron. That squadron was his work through the final months, as the remaining convoy routes were worn down. He retired on 15 September 1945 and died on 4 February 1960.