Structure of the Japanese Forces in South Pacific Mandate

Japan

Japan

Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

ese garrisons on the by-passed Pacific Islands 1944–1945, included South Pacific Mandate

South Pacific Mandate

The was the Japanese League of Nations mandate consisting of several groups of islands in the Pacific Ocean which came under the administration of Japan after the defeat of the German Empire in World War I.-Early history:Under the terms of the Anglo-Japanese Alliance, after the start of World...

 Force and nearest islands in period.

Commander-in-chief of South Pacific Detachment forces

• Boshiro Hosogaya
  Boshiro Hosogaya
  , was an admiral in the Imperial Japanese Navy during World War II.-Biography:Hosogaya was born to a farming family in Nozawa, Nagano prefecture in 1888. He graduated from the 36th class of the Imperial Japanese Naval Academy in 1908. He was ranked 16th in a class of 191 cadets. As a midshipman, he...
  
  : Governor-General of South Pacific Mandate, was also direct Commander-in-chief of South Pacific Mandate detachment. He represented the Japanese
  Empire of Japan
  The Empire of Japan is the name of the state of Japan that existed from the Meiji Restoration on 3 January 1868 to the enactment of the post-World War II Constitution of...
  
   central government and the Imperial Japanese Navy
  Imperial Japanese Navy
  The Imperial Japanese Navy was the navy of the Empire of Japan from 1869 until 1947, when it was dissolved following Japan's constitutional renunciation of the use of force as a means of settling international disputes...
  
  , the real power in the territory.

Kwajalein Atoll detachment

Japanese positions at Kwajalein

Kwajalein

Kwajalein Atoll , is part of the Republic of the Marshall Islands . The southernmost and largest island in the atoll is named Kwajalein Island. English-speaking residents of the U.S...

, Wotje, and Eniwetok (Enewetak

Enewetak

Enewetak Atoll is a large coral atoll of 40 islands in the Pacific Ocean, and forms a legislative district of the Ralik Chain of the Marshall Islands. Its land area totals less than , surrounding a deep central lagoon, in circumference...

) and Roi-Namur

Roi-Namur

Roi-Namur is an island in the northern part of the Kwajalein atoll in the Marshall Islands.Occupied by Japanese forces prior to World War II, it was the target of the U.S. 4th Marine Division in the Battle of Kwajalein, in February 1944....

 Atolls (3,600 Japanese defenders)

Japanese Navy units

• 66th Guard Unit (1,200 men), Captain Masanari Shiga
• Detachment of 4th Establishment Department (1,200 men)
• Total: 2,045 men

Japanese Army units

• 1st South-Seas Detachment (740 men)
• 107th Infantry Regiment (1,500 men)
• Total: 2,237 men

Japanese Navy units

• 64th Guard Unit (1,000 men), Captain Shinichi Yoshimi
• Chitose Air Unit (1,000 men)
• Establishment Department (900 men)
• Total: 2,959 men

Equipment

• 6 × 150 mm cannons
• 2 × 120 mm cannons
• 5 × 150 mm howitzers
• 6 × 127 mm AA guns

Japanese Army units

• Wotje Unit of 1st South-Seas Detachment (225 men)
• Wotje remainders of 2nd Battalion/2nd Mobile-Sea Brigade (199 men) led by Colonel Aso
• Wojte Armor Group-2nd Battalion/1st Sea-mobile Brigade
• Total: 424 men

Japanese Navy units

• 63rd Guard Unit (1,095 men), Rear Admiral Shoichi Kamada
• 252nd, 752nd, 755th Air Units (890 men)
• Detachment of 4th Establishment Department (822 men)
• Total: 2,940 men

Equipment

• 6 15 cm cannons
• 2 12 cm cannons
• 4 15 cm howitzers
• 2 field guns
• 1 regimental gun
• 10 127 mm AA guns

Japanese Army units

• 6th Company/1st Mobile-Sea Brigade (209 men)
• 7th Company/122nd Infantry Regiment (181 men)
• Total: 389 men

Japanese Navy

• 62nd Guard Unit (547 men), Captain Nisuke Masuda
• 4th Establishment Department
• Construction Unit
• Air Unit
• Total: 1,584 men

Japanese Army units

• 50th Independent Mixed Brigade (3,404 men), Major-General Katsumi Kitamura
• 331st to 335th Independent Infantry Battalions
• Tank Unit (9 Type 95 Light Tanks)
• Artillery Unit (4 field guns, 8 100 mm howitzers)
• AA Gun Unit (4 Type 88 75 mm AA Guns)
• Engineer Unit
• Signal Unit
• Hospital
• Total: 3,404 men

Japanese Navy units

• 44th Guard Unit (1,411 men), Commander Yoshinobu Miyata
• 216th Construction Unit (978 men)
• Detachment of 4th Establishment Department (616 men)
• Air Unit (85 men)
• other (131 men)
• Total: 3,221 men

• 50th Independent Mixed Brigade was reorganized in May 1944, from the following units on Mereyon; South-Seas 5th Detachment, 7th Detachment Unit (from 24th Division), 3rd Company/52nd AA Gun Battalion.

Japanese Navy units

• 42nd Guard Unit (600-900 men), Captain Jun Naito
• 3rd Detachment of 4th Signal Unit (36 men)
• Ponape Detachment of 4th Establishment Department (300 men)

Total: 2,000 men

Equipment

• 8 150 mm naval guns
• 8 80 mm naval guns
• 2 80 mm AA guns
• 2 127 mm AA guns

Japanese Army units

• 52nd Independent Mixed Brigade (3,322 men), Lieutenant General Masao Watanabe
  Masao Watanabe
  was a general in the Imperial Japanese Army during World War II.-Biography:Watanabe was the son of a former samurai retainer of the Kishiwada domain. His father was an elementary school teacher...
  
  
• 342nd to 345th Independent Infantry Battalions
• Tank Unit (9 Type 95 Light Tanks)
• Artillery Unit (6 Type 38 75 mm Field Guns)
• Engineer Unit
• Signal Unit
• Detachment of 107th Infantry Regiment (2,173 men)
• 2nd Battalion
• 3 Infantry Mortar Companies (12 Type 97 81 mm Infantry Mortars each)
• Machine Cannon Company(6 Type 98 20 mm AA Machine Cannons)
• Tank Company (9 Light Tanks)
• Total: 5,984 men

• 52nd Independent Mixed Brigade was reorganized in May 1944, from the following units on Ponape
  Pohnpei
  Not to be confused with Pompeii, the ancient city destroyed by Vesuvius in AD 79.Pohnpei "upon a stone altar " is the name of one of the four states in the Federated States of Micronesia , situated among the Senyavin Islands which are part of the larger Caroline Islands group...
  
  ; 3rd South-Seas Detachment, 2nd Battalion/5th Independent Mixed Regiment.

Japanese Army units

• 2nd South-Seas Detachment(1,901 men)-Lieutenant-General Yoshikazu Harada
• Detachment HQ
• Three Battalions
• Tank Company (9 Type 95 Light Tanks)
• Engineer Company
• 107th Infantry Regiment (1,910 men)
• Regimental HQ
• 1st Battalion:
• Battalion HQ
• 4 Infantry Companies
• Artillery Company (2 80 mm Armstrong naval guns)
• Mountain Gun Battalion (4 Type 94 Mountain Guns)
• Infantry Gun Company (2 47 mm AT guns, 6 37 mm AT guns)
• Infantry Mortar Company (8 infantry mortars)
• Total: 3,811 men

Japanese Navy units

• Kusaie Detachment of 42nd Guard Unit (119 men)
• Detachment of 4th Signal Unit (24 men)
• Detachment of 4th Establishment Department (640 men)
• Total: 700 men

Japanese Army units

• 4th South-Seas Detachment (700 men), Colonel Masatake Tobita
• Detachment HQ
• 3 Infantry Companies
• MG Company (8 Type 92 HMGs)
• Infantry Gun Company (4 infantry mortars, 4 AT guns)
• Tank Company (6 Medium Tanks)
• Detachment of 51st Independent Mixed Brigade (132 men)
• Total: 753 men

Japanese Navy units

• Detachment of 41st Guard Unit (250 men)
• 2 200 mm naval cannons
• 8 AA machine cannons
• 4th Meteorology Unit
• Air Base Crew
• Total: 257 men

Japanese Army units

• 11th Independent Mixed Regiment (2,769 men), Colonel Tatsuo Yasui
• Regimental HQ
• 1st Battalion (4 infantry guns, 2 mountain guns, 2 47 mm AT guns, 2 37 mm AT guns)
• 2nd Battalion (2 infantry guns, 2 AT guns)
• 3rd Battalion (2 infantry guns, 2 AT guns)
• Artillery Unit (8 field guns, 4 100 mm howitzers)
• Engineer Unit
• AA Gun Unit (6 Type 88 75 mm AA Guns)
• Signal Unit
• Total: 1,010 men

Japanese Navy units

• Detachment of 41st Guard Unit
• Total: 243 men

• The 1st and 2nd Battalions and some parts of the 11th Independent Mixed Regiment were moved to Truk due to the food shortage on the island. 335 Imperial Japanese Army soldiers and 211 Imperial Japanese Navy soldiers on the island died of hunger and an illness and 675 IJA soldiers and 32(!) IJN soldiers returned home from the island.

Truk Island Unit

Japanese base at Truk, the pivot of the Japanese position in South Pacific Mandate. Truk was a huge naval complex, the "Pearl Harbor

Pearl Harbor

Pearl Harbor, known to Hawaiians as Puuloa, is a lagoon harbor on the island of Oahu, Hawaii, west of Honolulu. Much of the harbor and surrounding lands is a United States Navy deep-water naval base. It is also the headquarters of the U.S. Pacific Fleet...

 of the Japanese". It had been under construction since 1937.

Japanese aviation facilities was Dublon (Tonoas),
Moen

Moen (island)

Moen, also called Weno or Wono, is an island in Truk Lagoon, the main island group of the state of Chuuk in the Federated States of Micronesia....

 (Weno

Weno

Weno is an island municipality of Chuuk State of the Federated States of Micronesia. It is located in the Chuuk Lagoon and serves as the main center of commerce and is also the state capital. It has a population of approximately 6,000 to 7,000 people.-External links:*...

),and Eten

Eten Island

Eten is an island in the Truk Lagoon, in the Federated States of Micronesia. It is located just to the south of Dublon Island. This small island was extensively bulldozed by Japanese forces during World War II to turn it into an airstrip....

 Atolls.

Truk District Group

• Under 52nd Division Commander
• LtGen Shunsaburo Mugikura

• Nucleus: 52nd Division
• 51st Independent Mixed Brigade
• 52nd Independent Mixed Brigade

Japanese Navy units

• 4th Fleet HQ - Vice Admiral Chuichi Hara
  Chuichi Hara
  -External links:*...
  
  
• 4th Base Force HQ
• 41st, 43rd, 47th, 48th Guard Units
• Total: 27,856 men

Equipment (1942)

• 18 80 mm naval guns
• 10 150 mm naval guns
• 280 mm AA guns
• 12 127 mm AA guns

Japanese Army units

• 31st Army HQ (128 men), Lieutenant-General Shunzaburo Mugikura
• 52nd Division
• Divisional HQ (298 men)
• 69th Infantry Regiment (2,694 men)
• 150th Infantry Regiment (2,136 men)
• Tank Unit (103 men)*
• Signal Unit (241 men)
• Transport Unit (105 men)
• Sea Transport Unit (1,132 men)
• Ordnance Service Unit (117 men)
• Field Hospital (649 men)
• 51st Independent Mixed Brigade (4,789 men), Major-General Kanenobu Ishuin
• Brigade HQ
• 336th to 341st Independent Infantry Battalions
• 1st Artillery Unit
• Engineer Unit
• AA Gun Unit
• Signal Unit
• 11th Independent Mixed Regiment (1,366 men)
• 9th Independent Engineer Regiment (483 men)
• 58th Anchorage HQ
• Total: 16,737 men

• Tank unit had no tanks, because the transport ship was sunk by air raid.

Japanese Army units

• 49th Independent Mix Brigade (4,066 men), Colonel Daihachi Itoh
• Brigade HQ
• 323rd to 330th Independent Infantry Battalions
• Artillery Unit (8 Type 95 75 mm Field Guns, 14 Type 91 100 mm Howitzers)
• AA Gun Unit (4 Type 88 75 mm AA Guns)
• Engineer Unit
• Signal Unit
• Special Field Hospital
• Total: 4,423 men

Japanese Navy units

• 46th Guard Unit (1,000 men), Captain Masamichi Tanaka
• 205th Construction Unit (1,000 men)
• Total: 1,494 men

• 49th Independent Mix Brigade was reorganized in May 1944, from the 4th Detachment Unit (from 12th Division) on Yap Island. The last Japanese garrison surrendered at Fais Island
  Fais Island
  Fais Island is a raised coral island in the eastern Caroline Islands in the Pacific Ocean, and forms a legislative district in Yap State in the Federated States of Micronesia...
  
   in the Yap group.

Palau District Group

• Under 14th Division Commander
• LtGen Sadao Inoue
• nucleus: 14th Division
• 49th and 53rd Independent Mixed Brigades.

Palau islands (Peleliu

Peleliu

Peleliu is an island in the island nation of Palau. Peleliu forms, along with two small islands to its northeast, one of the sixteen states of Palau. It is located northeast of Angaur and southwest of Koror....

) unit

There were 10,700 Japanese defenders under Colonel Kunio Nakagawa

Kunio Nakagawa

Colonel was the commander of Japanese forces which defended the island of Peleliu in the Battle of Peleliu which took place from 15 September to 27 November 1944. He inflicted heavy losses on attacking U.S. Marines and held Peleliu island for almost three months...

• Tank Unit/14th Division-Captain Amano

Japanese Army units

• 14th Division - Lieutenant-General Sadao Inoue
• 53rd Independent Mixed Brigade (6,000 men), Major-General Takeo Yamaguchi
• 347th to 351st Independent Infantry Battalions
• Artillery Unit
• Engineer Unit
• Transport Unit/1st Sea-Mobile Brigade (1,338 men)
• Tank Unit/6th South-Seas Detachment (7 Light Tanks)
• Palau Branch of 3rd Ship Transport HQ (1,480 men)
• 57th Line of Communication Area Unit (753 men)
• Total: 21,449 men

Japanese Navy units

• 30th Special Base Force (2,500 men), Vice-Admiral Kenmi Itoh
• Total: 8,286 men

• Less 2nd Infantry Regiment, 1st Battalion/59th Infantry Regiment, Tank Unit.

Commanders in Mariana Islands Units

Saipan was defended by 29,662 Japanese army and navy troops under Lt. General Yoshitsuga Saito and Admiral Chuichi Nagumo

Chuichi Nagumo

was a Japanese admiral in the Imperial Japanese Navy during World War II and one time commander of the Kido Butai . He committed suicide during the Battle of Saipan.-Early life:...

Saipan and Tinian Island area

• under 43rd Division Commander, LtGen Yoshitsugu Saito
  Yoshitsugu Saito
  - Notes :...
  
  
• nucleus: 43rd Division,
• 47th Independent Mixed Brigade.
• 5th Infantry Regiment(Tinian Island), Colonel Keishi Ogata
• 9th Tank Regiment(Saipan), Colonel Goshima
• Yokosuka 1st SNLF
• 55th Guard Unit
• Tank Unit/18th Infantry Regiment(Tinian), First Lieut. Sikamura
• Artillery Unit/47th Independent Mixed Brigade, Captain Yamane
• 3rd Independent Mountain Gun Regiment, Lt.Col. Nakajima
• Artillery Battalion/135th Infantry Regiment, Major Aikawa
• Artillery Battalion/136th Infantry Regiment, Major Yabuki

Japanese Navy units

• Navy Artillery
• 4 200 mm Naval Guns
• 14 150 mm Naval Guns
• 3 140 mm Naval Guns
• 4 120 mm Naval Guns
• 4 80 mm Naval Guns

Japanese Army units

• 9th Independent Mixed Regiment (1,995 men), Colonel Umahachi Tenba
• Total: 2,150 men

Japanese Army units

• 10th Independent Mixed Brigade (947 men), Major Shigeo Imagawa
• Total: 1,031 men

Japanese Navy unit

• Detachment of 41st Guard Unit (600 men). It was detached from 56th Guard Unit on Tinian
  Tinian
  Tinian is one of the three principal islands of the Commonwealth of the Northern Mariana Islands.-Geography:Tinian is about 5 miles southwest of its sister island, Saipan, from which it is separated by the Saipan Channel. It has a land area of 39 sq.mi....
  
  . After destruction of 56th Guard Unit, the command of the detachment on Rota
  Rota (island)
  Rota also known as the "peaceful island", is the southernmost island of the United States Commonwealth of the Northern Mariana Islands and the second southernmost of the Marianas Archipelago. It lies approximately 40 miles north-northeast of the United States territory of Guam...
  
   was changed to 41st Guard Unit on Truk.
• Total: 1,954 men

Southern Marianas District Group

The Japanese defenders of this largest Marianas group island numbered some 19,000 troops under Lt. General Hyo Takashima

Guam Island area

• 29th Division Commander, LtGen Hyo Takashina
• Units:
• 29th Division
• 48th Independent Mixed Brigade.
• 1st Company/9th Tank Regiment, First Lieut. Sachi
• 2nd Company/9th Tank Regiment, Captain Tsunenari Sato
• Tank Unit/29th Division, Captain Hideo Sato

Japanese Navy units

• 5th Special Base Force (Makin detachment), Lt.j.g. Seizo Ishikawa
• 3rd Special Base Force (Makin detachment)
• Makin Armor Detachment of 3rd Special Base Force (3 Type 95 Light Tanks)
• Total: 284 troops
• Aviation Personnel
• Total: 100 units
• 4th Fleet Construction Unit

Total: 276 men

All units complete the total of: 798 men under command of Lieutenant j.g. Seizo Ishikawa. Most of aviation or labor units had no combat training and were not assigned weapons or a battle station, also the number of actual armed combat troops on Makin

Makin (islands)

Makin is the name of a chain of islands located in the Pacific Ocean island nation of Kiribati, specifically in the Gilbert Islands.-Geography:...

 was no more than 300 men.

• Makin Naval Base:

A surface vessel and submarine port, with naval coastal defenses, possessed capacity to receive some Kawanishi H8K

Kawanishi H8K

|-See also:-References:NotesBibliography* Bridgeman, Leonard. "The Kawanishi H8K2 “Emily”" Jane’s Fighting Aircraft of World War II. London: Studio, 1946. ISBN 1-85170-493-0....

 "Emily" flying boat

Flying boat

A flying boat is a fixed-winged seaplane with a hull, allowing it to land on water. It differs from a float plane as it uses a purpose-designed fuselage which can float, granting the aircraft buoyancy. Flying boats may be stabilized by under-wing floats or by wing-like projections from the fuselage...

 bombers, Nakajima A6M2-N "Rufe" hydrofighters and Aichi E13A

Aichi E13A

-See also:-References:NotesBibliography* Dorr, Robert E. and Chris Bishop. Vietnam Air War Debrief. London: Aerospace Publishing, 1996. ISBN 1-874023-78-6....

1 "Jake" recon-hydroplanes.

Japanese Navy units

• 67th Guard Unit (1,367 men), Captain Hisayuki Soeda
• Yokosuka 2nd SNLF (769 men)
• Nauru Special Construction Unit/4th Construction
• Department (2,120 men)
• Total: 4,256 men

Equipment

• 4 150 mm Naval Guns
• 4 80 mm Naval Guns
• 4 Twin 127 mm AA Guns
• 12 25 mm MGs
• 10 130 mm MGs

Japanese Navy units

Makin

Makin (islands)

Makin is the name of a chain of islands located in the Pacific Ocean island nation of Kiribati, specifically in the Gilbert Islands.-Geography:...

, Apamama, Betio

Betio

Betio is an island and a town at the extreme southwest of South Tarawa in Kiribati. The main port of Tarawa Atoll is located there.-Overview:...

, and Tarawa

Tarawa Atoll

Tarawa is an atoll in the central Pacific Ocean, previously the capital of the former British colony of the Gilbert and Ellice Islands. It is the location of the capital of the Republic of Kiribati, South Tarawa...

 Atolls

• Special Naval Landing-Rear Admiral Keiji Shimbasaka
• Sasebo 7th Special Naval Landing Force (2,619 men at command of Rear-Admiral Takeo Sugai) also 4,800 naval troops.
• Tank Unit/Sasebo 7th SNLF (14 Type 95 Light Tanks) Commanded by Ensign Ohtani

Japanese Navy units

• 65th Guard Unit (2,000 men), Captain Shigematsu Sakaibara
  Shigematsu Sakaibara
  -Notes:...
  
  
• Total: 2,200 men

Equipment

• 4 twin 127 mm AA guns
• 4 80 mm AA guns
• 5 captured US 3-inch AA guns
• 2 captured US 5-inch naval guns
• 4 200 mm naval guns
• 4 150 mm naval guns
• 8 120 mm naval guns

Japanese Army units

• 13th Independent Mixed Regiment (1,939 men), Colonel Shigeji Chikamori
• Regimental HQ
• 1st Battalion
• 2nd Battalion
• Artillery Company
• 1st Tank Unit
• 2nd Tank Unit

Equipment

• 11 37 mm AT guns
• 4 47 mm AT guns
• 3 regimental guns
• 4 field guns
• 5 infantry guns
• 9 Type 95 Light Tanks
• 4 captured US 3-inch AA guns
• 4 captured US 5-inch naval guns

• Total: 1,939 men

• 13th Independent Mixed Regiment was reorganized in May 1944, from the following units on Wake Island
  Wake Island
  Wake Island is a coral atoll having a coastline of in the North Pacific Ocean, located about two-thirds of the way from Honolulu west to Guam east. It is an unorganized, unincorporated territory of the United States, administered by the Office of Insular Affairs, U.S. Department of the Interior...
  
  ; 3rd South-Sea Garrison Unit, 1st Battalion/5th Independent Mixed Regiment and 16th Tank Regiment.

Japanese Navy units

• Minami-tori-shima Guard Unit-Rear-Admiral Masata Matsubara
• Total: 742 men

Japanese Army units

• 12th Independent Mixed Regiment, Colonel Yoshiichi Sakata
• Three Infantry Battalions
• Field Gun Company (3 Type 38 75 mm Field Guns)
• Tank Company (9 Type 95 Light Tanks)
• Signal Company
• Total: 2,005 men

Japanese Army units

• Under 109th Division Commander (LtGen Tadamichi Kuribayashi
  Tadamichi Kuribayashi
  General was a haiku poet, diplomat, and General of the Imperial Japanese Army General Staff. He is best known for being overall commander of the Japanese garrison during the Battle of Iwo Jima....
  
  )
• Nucleus: 109th Division (Iwo Jima
  Iwo Jima
  Iwo Jima, officially , is an island of the Japanese Volcano Islands chain, which lie south of the Ogasawara Islands and together with them form the Ogasawara Archipelago. The island is located south of mainland Tokyo and administered as part of Ogasawara, one of eight villages of Tokyo...
  
  )
• Lieut. Colonel Nishi led 26th Tank Regiment
• 2nd Mixed Brigade Artillery Group HQ, Col. Kaido
• Artillery Unit/2nd Mixed Brigade, Major Maeda
• Artillery Battalion/145th Infantry Regiment, Captain Matsuda
• 20th Independent Mortar Battalion, Captain Mizutari
• 2nd Middle Infantry Mortar Battalion, Major Nakao
• 3rd Middle Infantry Mortar Battalion, Major Kobayashi
• Rocket Artillery Company, 1st Lt. Yokoyama
• 1st Independent Infantry Mortar Company, 1st Lt. Yamaki
• Artillery Company/26th Tank Regiment, 1st Lt. Kishi

Japanese Navy units

• Navy Artillery
• 4 150 mm Naval Guns
• 4 140 mm Naval Guns
• 7 120 mm Naval Guns
• 8 120 mm Short Naval Guns