Okinawa Battle: Japanese unit

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tigre
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Re: Okinawa Battle: Japanese unit

#16

Post by tigre » 22 Jun 2015, 23:21

Hello to all :D; something more......................

Japan's battle of Okinawa, April to June 1945 / by Thomas M. Huber.

Reorganization,

The total strength of the Japanese forces on Okinawa was about 100,000; 67,000 of these were in the IJA, 9,000 were in the IJN, and 24,000 were impressed Okinawans used mostly in service support roles. The strengths of the IJA main units were 32d Army headquarters, 1,070; 32d Army direct service units, 6,005; 24th Division, 14,360; 62d Division, 11,623; and 44th IMB, 4,485. These units accounted for only 38,000 of the IJA's 67,000-man complement, however. The remaining 29,000 men were in the specialized antiaircraft, sea-raiding, and airfield battalions.

It occurred to the 32d Army Staff, however, that these richly manned service units should be reorganized for ground combat. Between 13 and 20 February 1945, the 1st, 2d, 3d, 26th, 27th, 28th, and 29th Sea-Raiding Base Battalions were restructured and became the 1st, 2d, 3d, 26th, 27th, 28th, and 29th Independent Battalions. Only motorboat pilot and maintenance companies were left at the bases, and the remaining 600 men per battalion were withdrawn for use as light infantry battalions. The seven independent battalions, with about 4,500 troops altogether, were then distributed to the 24th and 62d Divisions and to the 44th IMB.

The 19th Air Sector Command became the 1st Specially Established Regiment and was assigned to defend, under 62d Division, the same Yontan and Kadena airfields it had recently built and maintained. The 1st Specially Established Brigade was created from elements of the 49th Line of Communications Command and placed under that unit's headquarters commander. It was stationed in the Naha-Yonabaru area under the command of the 62d Division. The 2d Specially Established Brigade was created under the 11th Shipping Group commander and was stationed on the southwestern end of Okinawa under the command of the 24th Division.

This reorganization of 21 March added 14,000 men to ground combat strength, leaving only 10,500 of the 67,000 IJA force in specialized service roles.

The 9,000 IJN troops on Oroku were also reorganized for ground combat at the end of March. This force was oriented almost entirely to naval and naval air activities.

In short, as the battle approached in February and March of 1945, 4,500 men from sea-raiding units, 14,000 men from various shipping and communications units, and 3,000 men from antiaircraft units, a total of 21,500 men of the 29,000 not already in major line units, were reorganized for potential service on the infantry line. To this total, 9,000 naval troops were also added.

Source: (Leavenworth papers, ISSN 0195-3451; no. 18)

More follows. Cheers. Raúl M 8-).

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Re: Okinawa Battle: Japanese unit

#17

Post by marek O. » 23 Jun 2015, 17:36

Hi Wellgunde,

I was planning to but since the Navy list is much shorter, here it is now:
HQ Okinawa NBF - co rearadm. Ota Minoru
cos cpt. Nakao [first name not known]
4th Naval Land Escort Unit - co rearadm. Ota
Naha Area Naval Personel Biuro - cpt. Fukuyoshi Yasuo
four Naval Anti Aircraft Artillery Units - I don't know their numbers, commanders, strenghts
15 batteries of Seashore artillery - only numbered known to me was 3rd [co warrant oficer Nomura Tokio] at Oroku
27th Torpedo Boats Division - cpt. Shiraishi Shinji
1st Naval Midget Submarines Unit "White Dragons" - lt. Kawai Gen
37th Naval Torpedo Repair Unit
Naval Torpedo Assembly Unit
Naval Transmission Station Oroku
Naval Mortar Company [150 men, 81 mm mortars]
Naval Magazines Department Sasebo, Naha Depot - cpt. Hamano Gunichi [he rather commanded whole Department then just Naha Depot]
Naval Transport Department Sasebo, Naha Depot
Naval Naha Shipyard, Naval Station Sasebo
Oroku Detachment, 951st Kokutai - cpt. Haneda Jiro
Naval Airfield Unit Nansei Shoto - cpt. Tanamachi Hitoshi
1st, 3rd, 5th, 10th Naval Navigational Assist Unit
226th, 3210th Naval Construction Units
22nd, 27th, 42nd Shinyo Units.

Regards,
Next Army part soon,
Marek


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Re: Okinawa Battle: Japanese unit

#18

Post by marek O. » 24 Jun 2015, 13:18

Hello, here is the next part:
24th ID -co lt. gen. Amamiya Tatsumi
cos col. Kitani Yoshio
22nd Infantry Regiment - col. Yoshida Masaru
32nd IR - col. Hongo Kikuji
89th IR - col. Kanayama Hitoshi
42nd FAR - col. Nishizawa Yueo
24th Reconessance R - mjr. Saita Yutaro
24th Engineer R - col. Shitama [no first name]
24th Transport R - col. Nakamura Unosuke
Divisional Communication Unit - cpt. Hoka Seiichiro
Div. Training Decontamination Unit - cpt. Gotorashi Masaguro
Div. Technical Repair Unit - cpt. Tanaka Shinzo
Div. Veterinary Hospital - cpt. Iwai Yoshigoro
Div. Water Purification and Supply Unit - cpt. Tanaka Shinzo
1st [mjr. Yasui Futaro], 2nd [mjr. Koike Naosuke] Divisional Field Hospital.

62nd ID - co lt. gen. Fujioka Takeo
cos col. Ueno Sadaomi
63rd IB - mjr. gen. Nakajima Tokutaro:
11th IIB - lt.col. Saurahi? Suishiro
12th IIB - lt.col. Katani Okiyoshi
13th IIB - col. Hara Shutatsu
14th IIB - cpt. Uchiyama Sahio
273rd IIB - [co unknown to me]
64th IB - mjr. gen. Arikawa Keiichi:
15th IIB - mjr. Meshitsuka Hosaburo
21st IIB - lt.col. Nishibayashi Kokai
22nd IIB - lt.col. Isozaki, no first name
23rd IIB -mjr. Yamamoto Kiichi
272nd IIB - cpt. Shimada, no first name
Divisional Engineer Unit - mjr. Kanaki Tokusaburo
Div. Communication Unit - mjr. Sakawa Kenichiro
Div. Transport Unit - mjr. Sugimoto Hideji
Div. Field Hospital - mjr. Kumakura Fukeru
Div. Veterinary Hospital - lt. Suzuki Shigeta.

44th Independent Mixed Brigade - co mjr. gen. Suzuki Shigeru
2nd Infantry Unit - col. Udo Takehiko
15th Ind. Mixed Regiment - col. Mita Seiko
FA Unit - cpt. Hara Hideo
Engineer Unit - cpt. Muramoto Fukuguro

5th Artillery Command - mjr. gen. Wada Kosuke:
1st FAR - col. Yamane Chuu
23rd FAR - col. Kamizaki Iharu
7th HAR - col. Higuchi Daihiko
100th Ind HA Battalion - lt.col. Kawamura Hidehito
1st [mjr. Tama Sakitake], 2nd Mortar Battalion [cpt. Matsuda Shunhiko]

21st AAA Command - co lt.col. Yoshida Kiyoshi:
27th Ind AAA Battalion - mjr. Tataki Zenkuro
79th [mjr. Morimoto Binsho], 80th [mjr. Suto Hisashichi], 81st Field AA Battalion [mjr. Umetsu Tetsuto]
103rd [no name], 104th [cpt. Nakata Shigetomo], 105th Ind. Automatic Artillery Battalion [mjr. Murakami Mito]

Rest, probably tomorrow.
Regards,
Marek

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Re: Okinawa Battle: Japanese unit

#19

Post by VJK » 24 Jun 2015, 17:22

Hi Marek,

A few supplements to your list:

32nd Army Intelligence - Maj. Yakumaru Kanenori
27th Field Water purification and Supply Unit - Lt. Col. Fujii Eitaro
27th Tank Reg. - Lt. Col. Murakami Otsu
32nd Army Field Technical Depot (I think this is the 32nd Field Arsenal) - Lt. Col. Tsuchida Kanjiro
32nd Army Field freight Depot - Col. Ito Kaoru
32nd Army Fortification Construction Unit - Capt. Muta Daisuke
14 Field Well Drilling Company (this was in fact attached to the 62nd Division)-Capt. Fujisawa Uraraotto? (藤澤 麗夫)
20 Field Well Drilling Company - Lt. Masao Araki
Okinawa Military Hospital - Lt. Col. Hiroike Bunkichi
36th Communication Regiment - Maj. Otake Motoharu
24 Engineer Reg. - I have Col. Kodama Hisamitsu
11 IIB - Lt. Col. Miura Hinodeshiro (三浦日出四郎)
273 IIB - Capt. Kusunose Ichichin (楠瀬一珍)
22 IIB - Capt. Isozaki Tamaki
272 IIB - Capt. Shimoda Naomi
103rd Ind. Automatic Artillery Battalion - Maj. Osaka Seiji

You'll find a pretty full list with COs (in Japanese) here: http://www.okinawa-sen.go.jp/units_list.html

Best regards,

VJK

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Re: Okinawa Battle: Japanese unit

#20

Post by marek O. » 24 Jun 2015, 22:13

Dear VJK,
Great data. Thank You very much for corrections and filling some of the gaps. Page is absolutely incredible. I'll spend some time to translate it. List contains whole of 32nd Army, not only on Okinawa. That's great.

Regards,
Marek

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Re: Okinawa Battle: Japanese unit

#21

Post by Mil-tech Bard » 25 Jun 2015, 20:45

Marek,

This is via something Fontessa provided to me --
In the library of the National Institute for Defense Studies, I found the combat report of the 32nd Radar Unit.

It mentions IJA radars in Ryukyu Islands, as follows.

(The 1st and 2nd Independent Radar Units were absorbed in the 32nd Radar Unit in April, 1945.)

I believe that "Fixed" and "Field" means Tachi-6 and Tachi-7 respectively. And I don't know the type of "Type4 Mobile".

Unit / Location / Type of a radar / Operation Freqency (Hz)
32nd Radar Unit / Tatsugo, Amami Oshima / Fixed / 80
32nd Radar Unit / North Airfield, Okinawa / Field / 100
32nd Radar Unit / North Airfield, Okinawa / Field / 98
32nd Radar Unit / Shuri, Okinawa / Field / 102
32nd Radar Unit / Shuri, Okinawa / Ficed / 72
32nd Radar Unit / Motobu, Okinawa / Type4 Mobile / 102
1st Ind. Radar Unit / Field / Minami Daito Jima / 99
1st Ind. Radar Unit / Field / Minami Daito Jima / 97
2nd Ind. Radar Unit / Miyako Jima / Field / 101
2nd Ind. Radar Unit / Miyako Jima / Field / 103
32nd Army Radar Unit / Ishigaki Jima / Type4 Mobile / 102
There were additional IJN radar units on Kume Jima, Miyako Jima, Ishigaki Jima, Aguni Jima, and Yonakuni Jima.

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Re: Okinawa Battle: Japanese unit

#22

Post by Mil-tech Bard » 25 Jun 2015, 20:47

Also from another fontessa post here on the AHF --
According to Senshi Sosho, the units below belonged to the 57th Army. Initially these were subordinated to the 32nd Army, but were transferred to the 57th Army after the end of Okinawa campaign. In the below, personnel and equipment show overall numbers of each unit.

◇ Amami Ohshima
・Main force of 6th Heavy Artillery Regiment (under 64th IMB): 997 men with 4 – 24cm howitzers, 2- 15cm 加農 CANNONs and 7 field guns
・220th ~ 222nd Specially Established Guard Companies: 126 men each
・Amami Ohshima Army Hospital: 40 men
* IJA called a gun of which ballistic trajectory is low and straight 加農 CANNON. Although it is as confusing as cannon, it was a kind of field heavy gun.

◇ Tokunoshima
64th Independent Mixed Brigade (IMB) HQ: 90 men
- Main force of 21st Independent Mixed Regiment (IMR): 2,230 men with 4 mountain guns and 4- 37mm AT guns
- Main force of 22nd IMR: same as 21st IMR
1 Wire and 1 Radio Platoon, 36th Signal Regiment: 110 men
71st Land Duty Company: 511 men
75rh Airfield Company: 226 men
3rd Company, 26th Shipping Engineer Regiment: 329 men
Tokunoshima Army Hospital: 40 men

◇ Kikaigashima
3rd Battalion, 22nd IMR

◇ Okino Erabu Jima
3rd Battalion (minus 1 platoon of 8th Company), 21st MIR

◇ Yoron Jima
1 platoon of 8th Company, 21st MIR

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Re: Okinawa Battle: Japanese unit

#23

Post by Mil-tech Bard » 25 Jun 2015, 20:48

One more from fontessa --
The below is the units in south Ryukyu Islands, Initially they belonged to the 32nd Army. And I think they were transferred to the 10th Area Army after the end of Okinawa Campaign. As you seen from the below, IJA thought this area important.

◇ Miyako Jima area
28th Division (28D) HQ: about 250 men
- 3rd Infantry Regiment: about 2,500 men with 4 Type 41 mountain guns and 4 Type 94 37mm AT guns
- 30th Infantry Regiment: Same as the above
- 28th Cavalry Regiment: about 530 men
- 28th Mountain Artillery Regiment: about 2,200 men with 24 Type 94 mountain guns and 12 Type 99 10cm howitzers (山地十榴)
- 28th Engineer Regiment: about 750 men
- 28th Division Signal Unit: about 240 men
- 28th Transport Regiment: 500 men
- 28th Division Gas Control Training Place: 12 men
- 28th Division Ordinance Repair Place: 12 men
- 28th Division 2nd Field Hospital: 287 men
- 28th Division 4th Field Hospital: 294 men
- 28th Division Veterinary Hospital: 20 men
- 28th Division Water Supply and Purification Department: about 250 men
59th Independent Mixed Brigade (IMB) HQ: about 150 men
- 393rd Independent Infantry Battalion (IIB): about 600 men with 2 Type 41 mountain guns and 4 Type 94 37mm AT guns
- 394th IIB: Same as above
- 395th IIB: Same as above
- 396th IIB: Same as above
- 59th IMB Artillery Unit: about 400 men with 18 Type 97? trench mortars
- 59th IMB Engineer Unit: about 280 men
- 59th IMB Signal Unit: about 200 men
60th IMB HQ: about 150 men
- 397th IIB: about 600 men with 2 Type 41 mountain guns and 4 Type 94 37mm AT guns
- 398th IIB: Same as above
- 399th IIB: Same as above
- 400th IIB: Same as above
- 60th IMB Artillery Unit: about 400 men with 18 Type 97? trench mortars
- 60th IMB Engineer Unit: about 280 men
- 60th IMB Signal Unit: about 200 men
18th Independent Machinegun Battalion: 334 men with 24 HMGs
5th Independent Rapid- firing Gun Battalion: about 490 men
3rd Company, 27th Tank Regiment: about 70 men with 11 Type 89 medium tanks and 1 Type 95 light tank
1st Battalion, 1st Field Heavy Artillery Regiment: 606 men with 12 Type 95 15cm howitzers
47th Specially Established Machine Cannon Unit: 85 men with 12 Type 96 25mm machine cannons
505th Specially Established Guard Engineer Unit: 930 men
4th Sea Raiding Squadron: 110 men with 100 special assault boats
4th Sea Raiding Base Battalion: 900 men
30th Sea Raiding Base Battalion: Same as above
1 Radar Station of 32nd Army Air Intelligence Unit
205th Airfield Battalion: 406 men
129th Field Airfield Construction Unit: 175 men
Main force of 284th Independent Motor Transport Company
Main force of 109th Land Duty Company: 351 men
8th Field Well Drilling Company
9th Field Well Drilling Company
16th Field Well Drilling Company
Main force of 8th Fortress Construction Company
2nd Mobile Ordinance Repair Unit: 237 men
Miyako Jima Army Hospital

◇ Ishigaki Jima area
28th Division 3rd Field Hospital: 287 men
45th IMB HQ: 60 men
- 271st IIB: 673 men with 2 infantry guns or 37mm rapid firing guns
- 298th IIB: Same as above
- 299th IIB: Same as above
- 300th IIB: Same as above
- 301th IIB: Same as above
- 45 IMB Engineer Unit: 173 men
19th Independent Machinegun Battalion: 334 men with 24 HMGs
8th Heavy Artillery Regiemt
48th Specially Established Machine Cannon Unit: 85 men with 12 Type 96 25mm machine cannons
209th Specially Established Guard Company (SEGC): 126 men
210th SEGC: Same as above
226th SEGC: Same as above
227th SEGC: Same as above
506h Specially Established Guard Engineer Unit: 930 men
1 Radar Station of 32nd Army Air Intelligence Unit
69th Airfield Battalion: 406 men
128th Field Airfield Construction Unit: 175 men
1 platoon of 284th Independent Motor Transport Company
1 platoon of 8th Fortress Construction Company
Funauki Army Hospital

◇ Daito Jima area
36th Infantry Regiment (28D)
Daito Jima Detachment (former 85th Line of Communications Guard Unit)
18th Independent Rapid- firing Gun Battalion: about 490 men
49th Specially Established Machine Cannon Unit: 85 men with 12 Type 96 25mm machine cannons
50th Specially Established Machine Cannon Unit: Same as above
211th Specially Established Guard Company 126 men
101th Specially Established Sea Duty Company
1 Radar Station of 32nd Army Air Intelligence Unit

fontessa

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Re: Okinawa Battle: Japanese unit

#24

Post by Wellgunde » 27 Jun 2015, 11:32

Miltech, Thanks for reminding us of these.
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Re: Okinawa Battle: Japanese unit

#25

Post by Mil-tech Bard » 28 Jun 2015, 16:17

Wellgunde wrote:Miltech, Thanks for reminding us of these.
You're welcome.

FYI, I think the "Type4 Mobile radars" are Tachi-18 mobile radars, in the bit from Fontessa above, based upon their frequency and mobile identification.

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Re: Okinawa Battle: Japanese unit

#26

Post by Wellgunde » 01 Jul 2015, 15:02

Basic order of battle information on the Battle of Okinawa in English comes from two sources, Japan's Battle of Okinawa, April - June 1945 (Leavenworth Paper #18) available as a pdf from the Combined Arms Research Library (CARL) and from Okinawa: The Last Battle (one of the Army "Green Books") also available as a pdf from the U.S. Army's military history website. The former derives much from the latter and both discuss unit capabilities, commanders, numbers of personnel, and weapons. The "gold standard" for the Okinawa IJA and IJN orders of battle are contained in the charts and maps accompanying Senshi Sosho volume 11 Army Operations in the Okinawa Area and 17 Okinawa Area Naval Operations. These are very detailed and include commanders, unit dates of arrival, and other information regarding different periods of the command. Another source are the intelligence annexes to the Operation Iceberg after action report.
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Re: Okinawa Battle: Japanese unit

#27

Post by Mil-tech Bard » 01 Jul 2015, 21:44

Wellgunde,

Do you have access to Senshi Sosho volume 17 Okinawa Area Naval Operations?

I am intensely curious about the IJN radar units involved in the Okinawa campaign.

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Re: Okinawa Battle: Japanese unit

#28

Post by marek O. » 02 Jul 2015, 08:10

Hello Wellgunde,

I have also a request/question concerning Senshi Sosho 17. If You have access to it, could You check one thing that is bothering me for years. Osprey's "Okinawa 1945. The Last battle." Campaign 96 [2002] on page 88 gives a photo with such caption: "An IJN lieutenant, commander of the 183rd Naval Attack Force Rifle Battalion, surrenders to the 7th Marines, 1st Marine Division, on Motobu Peninsula, 3rd September...". I'm just curious about the unit. It must have been created during the battle. Giving the numer wasn't probably the only one.

Regards,
Marek

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Re: Okinawa Battle: Japanese unit

#29

Post by Wellgunde » 02 Jul 2015, 09:54

Miltech and Marek: I will take a look for you. No index means some hard slogging.
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Re: Okinawa Battle: Japanese unit

#30

Post by Mil-tech Bard » 02 Jul 2015, 20:46

Wellgunde,

Oh thank you so much!

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