5th Fleet (Imperial Japanese Navy)

The IJN 5th Fleet (第五艦隊 (日本海軍)) 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 Battle of the Aleutian Islands.

China Expeditionary Fleet
The IJN 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 IJN 4th and IJN 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.

North Pacific Fleet
The IJN 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.

With the outbreak of World War II, and the Doolittle raid on Tokyo, the IJN 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 IJN 5th Fleet 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.

However, the IJN 5th Fleet was unable to prevent the recapture of Attu by American forces in May 1943, and from 5 August 1943 – 5 December 1944, the IJN 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 Southeast Area Fleet on 15 December 1944. On 5 February 1945, the Southeast Area Fleet became the IJN 10th Area Fleet, at which time the remnants of the IJN 5th Fleet's administrative structure were disbanded.

In Second Sino-Japanese War

 * Cruiser Division 9
 * Heavy cruiser Myōko (Flagship), Light cruiser JAPANESE CRUISER Nagara
 * Cruiser Division 10
 * Light cruiser Tenryū, JAPANESE CRUISER Tatsuta
 * Torpedo Squadron 5
 * Light cruiser JAPANESE CRUISER Yūbari
 * Destroyer Division 3
 * Destroyer JAPANESE DESTROYER Shiokaze, JAPANESE DESTROYER Yūkaze,,  JAPANESE DESTROYER Hokaze,  JAPANESE DESTROYER Shimakaze,  JAPANESE DESTROYER Yakaze,  JAPANESE DESTROYER Nadakaze
 * Destroyer Division 16
 * Destroyer Asagao, Yūgao, Fuyō, Karukaya
 * Destroyer Division 23
 * Destroyer Kikuzuki, Mikazuki, Mochizuki, Yūzuki
 * Carrier Division 3
 * Seaplane tender Kamoi, Auxiliary seaplane tender Kagu Maru, Kamikawa Maru
 * Carrier Division 4
 * Seaplane tender Notoro, Auxiliary seaplane tender Kinugasa Maru

Order of Battle at time of Pearl Harbor

 * Cruiser Division 21 (Based at Ōminato)
 * Light cruiser JAPANESE CRUISER Tama (Flagship), JAPANESE CRUISER Kiso, Auxiliary seaplane tender Kimikawa Maru (based at Horomushiro)
 * Cruiser Division 22 (based at Kushiro)
 * Auxiliary cruiser Akagi Maru, Asaka Maru, Awata Maru
 * Gunboat Division 10
 * Auxiliary gunboat Yoshida Maru, Magane Maru
 * Subchaser Division 66
 * Auxiliary subchaser Fumi Maru, No.2 Seki Maru, Auxiliary netlayer Kōgi Maru
 * Minesweeper Division 17
 * Auxiliary minesweeper No.5 Toshi Maru, No.8 Toshi Maru, Keinan Maru, No.10 Misago Maru
 * Patrol division 7
 * Support craft Hokuyō-Gō, Auxiliary support craft No.1 Sasayama Maru
 * 1st Platoon
 * Auxiliary patrol boat No.5 Fukuichi Maru, Chōkai Maru, No.5 Seiju Maru, Kairyū Maru
 * 2nd Platoon
 * Auxiliary patrol boat No.3 Yachiyo Maru, No.23 Toku Maru, No.1 Fuku Maru
 * 3rd Platoon
 * Auxiliary patrol boat Eikichi Maru, No.3 Shōsei Maru, Shōei Maru, No.2 Taihei Maru
 * 4th Platoon
 * Auxiliary patrol boat No.5 Ebisu Maru, No.2 Kaihō Maru, Kaijin Maru
 * 5th Platoon
 * Auxiliary patrol boat No.1 Nittō Maru, No.2 Nittō Maru, No.23 Nittō Maru
 * 6th Platoon
 * Auxiliary patrol boat No.25 Nittō Maru, Kōki Maru, Fuji Maru
 * No.7 Base Force (based at Chichi-jima)
 * Chichijima Naval Air Group
 * Direct control from headquarter of the fleet
 * Torpedo boat Sagi, Hato
 * Attached ships for the fleet
 * Oiler Shiriya
 * Auxiliary gunboat Kaihō Maru
 * Auxiliary transport ship Nissan Maru, Chōkō Maru, No.2 Tōkō Maru, Akashisan Maru

Order of Battle at time of Operation Cottage

 * Cruiser Division 21 (based at Horomushiro)
 * Heavy cruiser (Flagship), JAPANESE CRUISER Maya, Light cruiser JAPANESE CRUISER Tama, JAPANESE CRUISER Kiso
 * Cruiser Division 22
 * Auxiliary cruiser Akagi Maru, Asaka Maru, Awata Maru
 * Cruiser Destroyer Squadron 1 (based at Horomushiro)
 * Light cruiser JAPANESE CRUISER Abukuma
 * Destroyer Division 2 (This division was rented from CruDesron 4.)
 * Destroyer JAPANESE DESTROYER Samidare
 * Destroyer Division 6 (This division was rented from CruDesron 11.)
 * Destroyer JAPANESE DESTROYER Hibiki
 * Destroyer Division 9
 * Destroyer JAPANESE DESTROYER Asagumo, JAPANESE DESTROYER Usugumo
 * Destroyer Division 10 (This division was rented from CruDesron 10.)
 * Destroyer JAPANESE DESTROYER Yūgumo, JAPANESE DESTROYER Akigumo, JAPANESE DESTROYER Kazagumo
 * Destroyer Division 21 (Shimakaze was rented from CruDesron 2.)
 * Destroyer JAPANESE DESTROYER Shimakaze, JAPANESE DESTROYER Wakaba, JAPANESE DESTROYER Hatsushimo
 * Destroyer Division 31 (This division was rented from CruDesron 2.)
 * Destroyer JAPANESE DESTROYER Naganami
 * No.51 Special Base Force (based at Kiska)
 * Attached ships for the fleet
 * Submarine Flotilla 7
 * Submarine I-2, I-4, I-5, I-6
 * Escort ship Kunashiri
 * Auxiliary seaplane tender Kimikawa Maru
 * Auxiliary oiler Nippon Maru, Teiyō Maru

Order of Battle at time of Leyte Gulf

 * Cruiser Division 16 (They did not participate in the naval battle, because it was commanded to do transportation duty.)
 * Heavy cruiser JAPANESE CRUISER Aoba, Light cruiser JAPANESE CRUISER Kitakami, JAPANESE CRUISER Kinu, Destroyer JAPANESE DESTROYER Uranami
 * Cruiser Division 21
 * Heavy cruiser JAPANESE CRUISER Nachi (Flagship), JAPANESE CRUISER Ashigara
 * Light cruiser JAPANESE CRUISER Tama (She was lent to the 3rd Fleet.)
 * Light cruiser JAPANESE CRUISER Kiso (She did not participate in the naval battle, because it was commanded to do transportation duty.)
 * Cruiser Destroyer Squadron 1
 * Light cruiser JAPANESE CRUISER Abukuma
 * Destroyer Division 7
 * Destroyer JAPANESE DESTROYER Akebono, JAPANESE DESTROYER Ushio
 * Destroyer Division 18
 * Destroyer JAPANESE DESTROYER Shiranui, JAPANESE DESTROYER Kasumi
 * Destroyer Division 21 (It did not participate in the naval battle, because it was commanded to do transportation duty.)
 * Destroyer JAPANESE DESTROYER Hatsuharu, JAPANESE DESTROYER Wakaba, JAPANESE DESTROYER Hatsushimo

Order of Battle at time of Mindoro

 * Heavy cruiser JAPANESE CRUISER Ashigara (Flagship)
 * Cruiser Destroyer Squadron 31
 * Light cruiser JAPANESE CRUISER Isuzu
 * Destroyer Division 43
 * Destroyer Take, Ume, Momo, Sugi, Maki, Kaede
 * Destroyer Division 52
 * Destroyer Kashi, Hinoki
 * Coast Defence Division 21
 * Escort ship Manju, Kanju, Kasado, Miyake, Ikuna, Yaku
 * 933rd Naval Air Group (Based at Saiki)
 * Attached ships for fleet
 * Escort ship No.21, No.22, No.29, No.31, No.43

Commanders of the IJN 5th Fleet
Commander in chief

Chief of Staff