The 5th Fleet (第五艦隊, Dai-go Kantai) was a fleet of the Imperial Japanese Navy, active during the early portions of the Second Sino-Japanese War, and again in World War II, primarily in the Aleutian campaign, during which it was augmented and designated the Northern Area Force.
The 5th Fleet was initially formed on 1 February 1938 as part of the Japanese military emergency expansion program in the aftermath of the North China Incident of 1937. The initial plan was to construct 3rd, 4th and 5th China Area Fleets to cover the invasions of Japanese troops into the Chinese mainland, and to interdict and control commerce on the coasts. The 4th and 5th Fleets came under the operational control of the 2nd China Expeditionary Fleet. It participated in the Hainan Island Operation and other maritime interdiction operations off the Chinese coast. The fleet was disbanded on 15 November 1939 when its operations were merged into the China Area Fleet.
The 5th Fleet was resurrected on 25 July 1941, and tasked with patrols of northern Japanese waters from the northern portion of Honshū, through Hokkaidō, the Chishima Islands, and as far as the Bonin Islands to the east. With the threat of maritime invasion by the Soviet Union considered extremely remote, and with Japanese forces focused on attacking south (Nanshin-ron), the IJN 5th Fleet was considered of secondary importance and was only assigned a couple of light cruisers and smaller vessels.[1]
With the outbreak of World War II, and the Doolittle raid on Tokyo, the 5th Fleet was reinforced by a large number of converted armed merchant vessels. The operational plan for the Battle of Midway called for a diversionary strike north towards the Aleutian Islands. The cruisers of the 5th Fleet – designated the "Northern Area Force" after its augmentation for the operation[2] – covered the landings of Japanese troops on Attu and Kiska on 6–7 June 1942, and were in the Battle of the Komandorski Islands against the United States Navy on 27 March 1943.[3]
However, the IJN 5th Fleet was unable to prevent the recapture of Attu by American forces in May 1943, and – after the abolition of the Northern Area Force on 4–5 August 1943[4] – from 5 August 1943 to 5 December 1944, the 5th Fleet was reorganized under the operational control of the Northeast Area Fleet, which oversaw the withdrawal of Japanese forces from Kiska and reinforcement of the northern approaches to Japan.
Following Japan's withdrawal from the Aleutians, the Northeast Area Fleet was reassigned directly to the Philippines in October 1944. It participated in the Battle of Leyte Gulf, and surviving vessels were joined to the Southwest Area Fleet on 15 December 1944. On 5 February 1945, the Southwest Area Fleet became the IJN 10th Area Fleet, at which time the remnants of the 5th Fleet's administrative structure were disbanded.
^Dull, Battle History of the Imperial Japanese Navy
^Morison, Samuel Eliot, History of United States Naval Operations in World War II, Volume IV: Coral Sea, Midway and Submarine Actions, May 1942-August 1942, Boston: Little, Brown and Company, 1988, p. 169n.
^Morison, Samuel Eliot, History of United States Naval Operations in World War II, Volume VII: Aleutians, Gilberts, and Marshalls, June 1942-April 1944, Boston: Little, Brown and Company, 1984, p. 65n.
Imperial Japanese Navy
