| Kōsaku Aruga | |
| Native Name: | 有賀幸作 |
| Native Name Lang: | jpn |
| Birth Date: | 21 August 1897 |
| Birth Place: | Asahi, Kamiina, Nagano, Japan |
| Death Place: | Southwest Kyūshū Sea |
| Nickname: | Chimney Man |
| Serviceyears: | 1917–1945 |
| Rank: | Vice Admiral (posthumous) |
| Commands: | Yūgao, Fuyō,,,,, 1st Minesweeper Division, 11th Destroyer Division, 4th Destroyer Division,, |
| Battles: | |
, was a career officer in the Imperial Japanese Navy during World War II. He commanded the battleship during its final mission, Operation Ten-Go.
Aruga was a native of Nagano prefecture, and graduated from the 45th class of the Imperial Japanese Navy Academy in 1917, ranked 58th of 89 cadets. He served his midshipman duty on the cruiser and battleship Hyūga, and completed naval artillery and torpedo warfare coursework from 1918 to 1919. After he was commissioned as an ensign, he served on a number of destroyers. From November 1922-November 1923, he was assigned to the battleship . After his promotion to lieutenant in December 1923, he served as chief torpedo officer on the destroyers and, followed by the light cruisers and .[1]
After his promotion to lieutenant commander in 1929, Aruga received his first command; the destroyer . This was followed by in 1930,, Akikaze in 1932, in 1933 and in 1934. After a shore assignment to the Chinkai Guard District from 1935 to 1937, Aruga returned to sea as the executive officer on the cruiser . He subsequently commanded 1st Minesweeper Division and Destroyer Division 11 (DesDiv 11), and was promoted to captain in November 1940.[1]
In June 1941, Aruga was in command of DesDiv 4, which participated in the Battle of Midway and in the Battle of the Eastern Solomons.[2]
In March 1943, Aruga was reassigned to command the heavy cruiser .[3] Recalled to Japan in June 1944 after he developed malaria, Aruga served as chief instructor at the Torpedo School until November of that year, when he was reassigned to the 2nd Fleet. On 25 November 1944, he was given command of the battleship .[4]
In April 1945, under Operation-Ten Gō, Yamato was assigned on a suicide mission against the American forces at the Battle of Okinawa. Given only enough fuel for a one-way mission and only a cruiser and eight destroyers as an escort, Yamato was to wreak havoc on the American landing operation, and to beach herself on the Okinawa shore as a coastal fortress.[5] On April 7, 1945, Yamato was sunk by waves of U.S. Navy carrier-based aircraft. Aruga went down with his ship. He was posthumously promoted two steps in rank to vice admiral.[6]
Some sources render his last name as Ariga;[5] the difference is due to an alternate reading of the first kanji character in his family name.