was an admiral in the

Imperial Japanese Navy The Imperial Japanese Navy (IJN; Kyūjitai: Shinjitai: ' 'Navy of the Greater Japanese Empire', or ''Nippon Kaigun'', 'Japanese Navy') was the navy of the Empire of Japan from 1868 to 1945, when it was dissolved following Japan's surrend ...

and Naval Minister during

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing ...

Biography

Oikawa was born into a wealthy family in rural Koshi County,

Niigata Prefecture is a prefecture in the Chūbu region of Honshu of Japan. Niigata Prefecture has a population of 2,227,496 (1 July 2019) and is the fifth-largest prefecture of Japan by geographic area at . Niigata Prefecture borders Toyama Prefecture and ...

, but was raised in

Morioka city is the capital city of Iwate Prefecture located in the Tōhoku region of northern Japan. On 1 February 2021, the city had an estimated population of 290,700 in 132,719 households, and a population density of . The total area of the city is . G ...

, Iwate prefecture in northern Japan. He was a graduate of the 31st class of the

Imperial Japanese Naval Academy The was a school established to train line officers for the Imperial Japanese Navy. It was originally located in Nagasaki, moved to Yokohama in 1866, and was relocated to Tsukiji, Tokyo in 1869. It moved to Etajima, Hiroshima in 1888. Students st ...

, ranking 76th out of 188 cadets. As a midshipman, he served on the cruisers and . During the

Russo-Japanese War The Russo-Japanese War ( ja, 日露戦争, Nichiro sensō, Japanese-Russian War; russian: Ру́сско-япóнская войнá, Rússko-yapónskaya voyná) was fought between the Empire of Japan and the Russian Empire during 1904 and 1 ...

, still as a midshipman, he served on the during the Battle of Tsushima. As a

lieutenant A lieutenant ( , ; abbreviated Lt., Lt, LT, Lieut and similar) is a commissioned officer rank in the armed forces of many nations. The meaning of lieutenant differs in different militaries (see comparative military ranks), but it is often ...

, Oikawa served on the cruiser , and the battleship . He was given his first command, the destroyer on 28 April 1911. He subsequently served on the , before attending the Naval Staff College in 1914. On graduation, Oikawa was promoted to

lieutenant commander Lieutenant commander (also hyphenated lieutenant-commander and abbreviated Lt Cdr, LtCdr. or LCDR) is a commissioned officer rank in many navies. The rank is superior to a lieutenant and subordinate to a commander. The corresponding ran ...

, and was appointed aide-de-camp to

Crown Prince A crown prince or hereditary prince is the heir apparent to the throne in a royal or imperial monarchy. The female form of the title is crown princess, which may refer either to an heiress apparent or, especially in earlier times, to the wi ...

Hirohito in 1915–1922. After his promotion to captain on 1 December 1923, Oikawa was assigned the cruiser , followed by the the following year. He then served in a number of staff positions until his promotion to rear admiral on 10 December 1928. In 1930, Oikawa was appointed to the

Imperial Japanese Navy General Staff The was the highest organ within the Imperial Japanese Navy. In charge of planning and operations, it was headed by an Admiral headquartered in Tokyo. History Created in 1893, the Navy General Staff took over operational (as opposed to adminis ...

, and in 1932 became Director of the Imperial Japanese Naval Academy. He was promoted to vice admiral on 15 November 1933. Oikawa strongly supported the London Naval Treaty while a member of the Imperial Japanese Navy General Staff, and was thus a member of the

Treaty Faction The was an unofficial and informal political faction within the Imperial Japanese Navy in the 1920s-1930s of officers supporting the Washington Naval Treaty. Background The ''Washington Naval Treaty'', also known as the ''Five-Power Treaty'', ...

within the navy. Oikawa was subsequently appointed Commander in Chief of the

IJN 3rd Fleet The was a fleet of the Imperial Japanese Navy (IJN), which was created, and subsequently disbanded on six separate occasions and revived on five separate occasions. =History= Russo-Japanese War First established on 28 December 1903, the 3rd Fl ...

(1935),

Imperial Japanese Navy Aviation Bureau The of the Ministry of the Navy of Japan was responsible for the development and training of the Imperial Japanese Navy Air Service. In 1941 it was headed by Vice-Admiral Eikichi Katagiri and was organized as follows: * General Affairs Department ...

(1936),

China Area Fleet The was a fleet of the Imperial Japanese Navy organized after the Battle of Shanghai. It reported directly to the Imperial General Headquarters and had the same organizational level as the Combined Fleet. This article handles their predecessor fl ...

(1938) and

Yokosuka Naval District was the first of four main administrative districts of the pre-war Imperial Japanese Navy. Its territory included Tokyo Bay and the Pacific Ocean, Pacific coasts of central and northern Honshū from the Kii Peninsula to Shimokita Peninsula. Its h ...

(1940). He was promoted to full admiral on 15 November 1939. Oikawa was appointed as Minister of the Navy in the second and third cabinets of

Prime Minister A prime minister, premier or chief of cabinet is the head of the cabinet and the leader of the ministers in the executive branch of government, often in a parliamentary or semi-presidential system. Under those systems, a prime minister i ...

Fumimaro Konoe between 5 September 1940 and 18 October 1941. While Navy Minister, he strove to maintain ties with the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...

, and instructed his

naval attaché A navy, naval force, or maritime force is the branch of a nation's armed forces principally designated for naval and amphibious warfare; namely, lake-borne, riverine, littoral, or ocean-borne combat operations and related functions. It includ ...

s in

Washington DC ) , image_skyline = , image_caption = Clockwise from top left: the Washington Monument and Lincoln Memorial on the National Mall, United States Capitol, Logan Circle, Jefferson Memorial, White House, Adams Morgan, ...

to work together with the Japanese ambassador to prevent war from breaking out. Likewise, he strongly opposed suggestions that Japan should declare war on the

Soviet Union The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, ...

in early 1941.Fuller, Shokan: Hirohito's Samurai He continued to serve as Naval Councilor to near the end of World War II and was Chief of the Navy General Staff in late 1944 but resigned in May 1945 and was replaced by an Ōita native

Toyoda Soemu was an admiral in the Imperial Japanese Navy in World War II. Biography Early career Toyoda was born in what is now part Kitsuki city, Ōita Prefecture. He graduated from the 33rd class of the Imperial Japanese Navy Academy in 1905, ranked 26 ...

in an attempt to soften down the

Imperial Japanese Army The was the official ground-based armed force of the Empire of Japan from 1868 to 1945. It was controlled by the Imperial Japanese Army General Staff Office and the Ministry of the Army, both of which were nominally subordinate to the Emperor o ...

's Ōita-born leadership. Oikawa retired from active duty on 5 September 1945.

References

Books

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Notes

External links

* * {{DEFAULTSORT:Oikawa, Koshiro 1883 births 1958 deaths People from Morioka, Iwate Imperial Japanese Navy admirals Japanese military personnel of the Russo-Japanese War Japanese admirals of World War II Ministers of the Imperial Japanese Navy