- Structure of the Imperial Japanese forces in the South Pacific Mandate
Structure of the Japanese Forces in South Pacific Mandate
Japan ese garrisons on the by-passed Pacific Islands 1944–1945, includedSouth Pacific Mandate Force and nearest islands in period.South Pacific Mandate DetachmentCommander-in-chief of South Pacific Detachment forces
*
Boshiro Hosogaya : Governor-General of South Pacific Mandate, was also direct Commander-in-chief of South Pacific Mandate detachment. He represented the Japanese central government and theImperial Japanese Navy , the real power in the territory.Marshall Islands UnitKwajalein Atoll detachmentJapanese positions at
Kwajalein ,Wotje , andEniwetok (Enewetak ) andRoi-Namur Atolls (3,600 Japanese defenders)Kwajalein Atoll Fortress
Japanese Army units
*Colonel Aso: Commanded 2nd Battalion and 1st Sea-mobile Brigade
Eniwetok Atoll Fortress
Japanese Army units
*First Lieut. Ichikawa: Led Tank Company/1st Sea-mobile Brigade
Mili Atoll Fortress
Mili Japanese Navy units
*66th Guard Unit (1,200 men), Captain
Masanari Shiga
*Detachment of 4th Establishment Department (1,200 men)
*Total: 2,045 menJapanese Army units
*1st South-Seas Detachment (740 men)
*107th Infantry Regiment (1,500 men)
*Total: 2,237 menWotje Atoll Fortress
Wotje 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 menEquipment
*6 × 150 mm cannons
*2 × 120 mm cannons
*5 × 150 mm howitzers
*6 × 127 mm AA gunsJapanese 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 menMaleolap Atoll Fortress
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 menEquipment
*6 15cm cannons
*2 12cm cannons
*4 15cm howitzers
*2 field guns
*1 regimental gun
*10 127 mm AA gunsJapanese Army units
*6th Company/1st Mobile-Sea Brigade (209 men)
*7th Company/122nd Infantry Regiment (181 men)
*Total: 389 menJaluit Island Fortress
Japanese Navy
*62nd Guard Unit (547 men), Captain
Nisuke Masuda
*4th Establishment Department
*Construction Unit
*Air Unit
*Total: 1,584 menJapanese Army units
*2nd Battalion/1st South-Seas Detachment (727 men)
*Total: 727 menMereyon Island Fortress
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 menJapanese 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.Caroline Islands Detachment
= Ponape Island Fortress=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 menEquipment
*8 150 mm naval guns
*8 80 mm naval guns
*2 80 mm AA guns
*2 127 mm AA gunsJapanese Army units
*52nd Independent Mixed Brigade (3,322 men), Lieutenant General
Masao Watanabe
*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; 3rd South-Seas Detachment, 2nd Battalion/5th Independent Mixed Regiment.
Kusaie Island Force
= Kusaie Island Fortress=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 menJapanese 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 menMortlock Island Detachment
Mortlock Island Fortress
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 menJapanese 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 menEnderby Island Unit
Enderby Island Fortress
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 menJapanese 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.
=Imperial Army Headquarters (Carolines)=Truk Island UnitJapanese base at
Truk , the pivot of the Japanese position in South Pacific Mandate. Truk was a huge naval complex, the "Pearl Harbor of the Japanese". It had been under construction since 1937.Japanese aviation facilities was
Dublon (Tonoas ),Moen (Weno ),and Eten Atolls.Truk District Group*Under 52nd Division Commander
*LtGenShunsaburo Mugikura *Nucleus: 52nd Division
*51st Independent Mixed Brigade
*52nd Independent Mixed BrigadeTruk Atoll Fortress
Japanese Navy units
*4th Fleet HQ - Vice Admiral
Chuichi Hara
*4th Base Force HQ
*41st, 43rd, 47th, 48th Guard Units
*Total: 27,856 menEquipment (1942)
*18 80 mm naval guns
*10 150 mm naval guns
*280 mm AA guns
*12 127 mm AA gunsJapanese 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-GeneralKanenobu 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 Yap Island Detachment
Yap Island Fortress
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 menJapanese 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 in theYap group .Palau Island Detachment
Palau District Group*Under 14th Division Commander
*LtGenSadao Inoue
*nucleus: 14th Division
*49th and 53rd Independent Mixed Brigades.Palau islands (
Peleliu ) unitThere were 10,700 Japanese defenders under Colonel
Kunio Nakagawa
*Tank Unit/14th Division-Captain Amano Babelthuap Island Fortress (
Palau Islands )Japanese Army units
*14th Division - Lieutenant-General
Sadao Inoue
*53rd Independent Mixed Brigade (6,000 men), Major-GeneralTakeo 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 menJapanese 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.
Mariana Islands Unit
*
Mariana Islands unit (Saipan andTinian )Commanders in Mariana Islands Units
Saipan was defended by 29,662 Japanese army and navy troops under Lt. General
Yoshitsuga Saito and AdmiralChuichi Nagumo Northern Mariana District Group
Saipan and Tinian Island area
*under 43rd Division Commander, LtGen
Yoshitsugu Saito
*nucleus: 43rd Division,
*47th Independent Mixed Brigade.
*5th Infantry Regiment(Tinian Island), ColonelKeishi 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 YabukiJapanese 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 GunsPagan Island Fortress
Japanese Army units
*9th Independent Mixed Regiment (1,995 men), Colonel
Umahachi Tenba
*Total: 2,150 menJapanese Navy units
*Guard unit (300 men). The unit is unknown.
*Total: 344 menRota Island Fortress
Japanese Army units
*10th Independent Mixed Brigade (947 men), Major
Shigeo Imagawa
*Total: 1,031 menJapanese Navy unit
*Detachment of 41st Guard Unit (600 men). It was detached from 56th Guard Unit on
Tinian . After destruction of 56th Guard Unit, the command of the detachment on Rota was changed to 41st Guard Unit onTruk .
*Total: 1,954 menGuam Island Fortress
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, CaptainTsunenari Sato
*Tank Unit/29th Division, CaptainHideo Sato Other Japanese Force Pacific Sea Detachments
=Japanese detachment in Makin Atoll (1943)=Butaritari Fortress
Japanese Navy units
*5th Special Base Force (Makin detachment), Lt.j.g.
Seizo Ishikawa
*3th 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 UnitTotal: 276 menAll 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 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 "Emily"flying boat bombers,Nakajima A6M2-N "Rufe" hydrofighters andAichi E13A 1 "Jake" recon-hydroplanes.Nauru Island detachment
Nauru Island Fortress
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 menEquipment
*4 150 mm Naval Guns
*4 80 mm Naval Guns
*4 Twin 127 mm AA Guns
*12 25 mm MGs
*10 130 mm MGsOcean island Unit
Ocean Island Fortress
Japanese Navy unit
*Ocean Detachment of 67th Guard Unit (760 men)
Gilberts islands detachmentTarawa Atoll Fortress
Japanese Navy units
Makin,
Apamama ,Betio , and Tarawa Atolls
*Special Naval Landing-Rear AdmiralKeiji 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 OhtaniWake Island DetachmentWake Island Fortress
Japanese Navy units
*65th Guard Unit (2,000 men), Captain
Shigematsu Sakaibara
*Total: 2,200 menEquipment
*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 gunsJapanese 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 UnitEquipment
*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 ; 3rd South-Sea Garrison Unit, 1st Battalion/5th Independent Mixed Regiment and 16th Tank Regiment.Marcus island Detachment
Marcus Island Fortress
Equipment
Japanese Navy units
*Minami-tori-shima Guard Unit-Rear-Admiral
Masata Matsubara
*Total: 742 menJapanese 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 menOgasawara island Detachment
=Ogasawara (Bonins) District Group =Japanese Army units
*Under 109th Division Commander (LtGen
Tadamichi Kuribayashi )
*Nucleus: 109th Division (Iwo Jima )
*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. KishiJapanese 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
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