Antiaircraft artillery regiments

[john whitman]

Good evening fontessa:

//homepage1.nifty.com/kitabatake/rikukaigun45.2.html and //www.jyai.net/military/data-02/Anti-Airc ... ent001.htm say that three antiaircraft artillery regiments were created in 1942. Is this correct? Were these two- or three-battalion organizations? I believe that the 25th was a two-battalion regiment. Did they all have 75mm cannon?

I was surprised to see that no antiaircraft regiments were created in 1943. Is this correct?

John

[hisashi]

For www.jyai.net, files Anti-Aircraft-Gun-Regiment001,002,003 and 004 makes a set. Note that in 1943 some AA gun regiment was renamed (or created) as 防空連隊 (boku-rentai, anti-air regiment). 31th boku-rentai was disbanded in 1944 but the other boku-rentai were again renamed as AA-artillery regiment (高射砲連隊).

AA-arty 1st regiment was raised in 1925. As all other regiment-sized units, the organization differed not only periodically, but also among the troops in each period. This article may help you.
http://www2u.biglobe.ne.jp/~surplus/tokushu28.htm

[fontessa]

Good morning John,

say that three antiaircraft artillery regiments were created in 1942. Is this correct?

Yes, it is correct.

Were these two- or three-battalion organizations?

The organization of an AAA regiment was as follows.
- HQ
- 1st AAA battalion
- 2nd AAA battalion
- 1 searchlight battalion

Did they all have 75mm cannon?

I guess that most regiments were equipped with Type 88 7 cm AA guns of which accurate caliber was 7.5cm.

I was surprised to see that no antiaircraft regiments were created in 1943. Is this correct?

Yes, it is correct. But 13 independent AAA battalions and 9 independent AAA companies were organized in 1943. The total number of AA guns for these battalions and companies was equivalent with that for 8 AAA regiments. I think that it was important for the Army to disperse AA guns than to deploy these intensively. (6 independent field searchlight companies were organized in 1943, too.)

fontessa

[john whitman]

Hello hisashi:

Than you for these references. I have studied //www2u.biglobe.ne.jp/~surplus/tokushu28.htm, and it has some nice information, especially about the prewar organizations. I was disappointed, however, that there was so little about deployments and actions outside Japan.

John

[john whitman]

Good evening fontessa:

Thanks for your response.

When you say that nine independent antiaircraft companies were organized in 1943, are these the 7.7mm heavy machine gun independent field antiaircraft guns companies 独立野戦高射砲 中隊 ? Can you tell me the unit designations of the nine that were organized in 1943? Is there a JACAR list of all these independent field antiaircraft guns companies?

You mentioned that there was usually one searchlight battalion to each regiment. I have not seen any reference to a searchlight battalion traveling with the 25th Antiaircraft Artillery Battalion to the Marinas in 1944. Did a searchlight battalion accompany the 25th to the Marianas?

John

[fontessa]

Good evening John,

When you say that nine independent antiaircraft companies were organized in 1943, are these the 7.7mm heavy machine gun independent field antiaircraft guns companies 独立野戦高射砲 中隊 ?

Yes I meant 独立野戦高射砲中隊. These were equipped with antiaircraft cannons.

Can you tell me the unit designations of the nine that were organized in 1943?

43rd ~ 49th: 2nd Area Army
50th ~ 51st: 2nd Army

Is there a JACAR list of all these independent field antiaircraft guns companies?

Unfortunately, JACAR does not have a list of company level units.

You mentioned that there was usually one searchlight battalion to each regiment. I have not seen any reference to a searchlight battalion traveling with the 25th Antiaircraft Artillery Battalion to the Marinas in 1944. Did a searchlight battalion accompany the 25th to the Marianas?

According to Senshi Sosho, the deployment of the 25th Antiaircraft Artillery Regiment were as follows.
- Pagan: HQ, 1st Btn HQ, 1st Co, 2nd Co, 3rd Btn HQ and 7th Co
- Saipan: 6th Co and 8th Co
- Mortlock: 3rd Co
- Enderby: 4th Co
- Truk: 2nd Btn HQ, 5th Co and 9th Co
The 3rd Battalion (7th, 8th and 9th Companies) was a searchlight battalion.

fontessa

[john whitman]

Good evening fontessa:

Thanks for this very useful information. I have good information on some of the marus in East Pine No. 2 as shown below.
Convoy East Pine No. 2, departed Yokohama 12 March 1944, arrived Saipan 19 March.

Hibi Maru (5,874 tons) departed Pusan 1 March and Tajima Maru (7,296 tons with about 4,500 men) departed Pusan 3 March. They carried:

1st Expeditionary Unit
25th Infantry Group Headquarters, 25th Division
3rd Battalion, 14th Infantry, 25th Division
3rd Battalion, 40th Infantry, 25th Division
3rd Battalion, 10th Infantry, 10th Division
3rd Battalion, 89th Infantry, 24th Division (618 men)
Headquarters, 3rd Independent Mountain Artillery Regiment
1st Battalion, 3rd Independent Mountain Artillery Regiment
3rd Battalion, 10th Artillery, 10th Division
3rd Company, 25th Engineers, 25th Division
6th Company, 2nd Battalion, 25th Antiaircraft Artillery Regiment
8th Company, 3rd Battalion, 25th Antiaircraft Artillery Regiment (searchlight)

Shinsei Maru No. 1 (5,873 tons) departed Pusan 3 March. She carried:

3rd Expeditionary Unit 2,769 men
8th Infantry Group Headquarters, 8th Division
1st Battalion, 5th Infantry, 8th Division
1st Battalion, 17th Infantry, 8th Division
3rd Battalion, 31st Infantry, 8th Division (587 men)
3rd Battalion, 8th Artillery, 8th Division
3rd Company, 8th Engineers, 8th Division
4th Company, 1st Battalion, 25th Antiaircraft Artillery Regiment

Takaoka Maru (7,006 tons) departed Pusan 3 March. She carried:

5th Expeditionary Unit
71st Infantry Group Headquarters, 71st Division
3rd Battalion, 87th Infantry, 71st Division
3rd Battalion, 88th Infantry, 71st Division
1st Battalion, 71st Artillery, 71st Division
3rd Company, 71st Engineers, 71st Division
Headquarters, 25th Antiaircraft Artillery Regiment
Headquarters, 1st Battalion, 25th Antiaircraft Artillery Regiment and 1st and 2nd Companies
Headquarters, 3rd Battalion (searchlight) and 7th Company, 25th Antiaircraft Artillery Regiment
(at Yokohama, the following units boarded Takaoka Maru (or Tajima Maru) and Hibi Maru)
Headquarters, 31st Army, 278th Independent Truck Company, one tank company, one machine cannon company, and 1st, 2nd, and 3rd Mortar Companies, all belonging to 18th Infantry, 29th Division. These units avoided the disastrous sinking of Sakito Maru in Convoy East Pine No. 1 that destroyed the 18th Infantry.

Tamahoko Maru (6,780 tons) departed Pusan 3 March (about 6,000 men): She carried:

6th Expeditionary Unit
Headquarters, 11th Infantry Group, 11th Division (256 men)
3rd Battalion, 12th Infantry, 11th Division (617 men)
3rd Battalion, 24th Infantry, 12th Division
3rd Battalion, 43rd Infantry, 11th Division (617 men)
1st Battalion, 44th Infantry, 11th Division (617 men)
3rd Battalion, 46th Infantry, 12th Division
3rd Battalion, 48th Infantry, 12th Division
3rd Battalion, 11th Mountain Artillery, 11th Division (367 men)
3rd Battalion, 24th Artillery, 12th Division
3rd Company, 11th Engineers, 11th Division (188 men)
3rd Company, 18th Engineers, 12th Division
Headquarters, 52nd Field Antiaircraft Artillery Battalion and 2nd Company

Tsushima Maru (6,754 tons) departed Pusan 3 March. She carried:

8th Expeditionary Unit
2nd Independent Garrison Headquarters, Korea Army
3rd Battalion, 73rd Infantry, 19th Division
3rd Battalion, 75th Infantry, 19th Division
3rd Battalion, 76th Infantry, 19th Division
3rd Battalion, 25th Mountain Artillery, 19th Division
3rd Company, 19th Engineers, 19th Division
Headquarters, 2nd Battalion, 25th AAA Regiment
5th Company, 2nd Battalion, 25th AAA Regiment
9th Company, 3rd Battalion, 25th AAA Regiment (searchlight)

Kokuyo Maru carried:

1,029 sailors, antiaircraft guns and equipment, reinforcements for the 54th Naval Guard Force on Guam.

aboard other marus

218th Naval Construction Unit
233rd Naval Construction Units (350 men)

Please note in my chart that I do not show the movement of 3rd Company, 25th AAA Regiment (as you say, to Mortlock). Do you know when it travelled to the Marianas?

I have no information on what units the following ships carried:
Miho Maru, 4,667 tons
Awa Maru, 4,524
Ryuka Maru, 2,813
Atlantic Maru, 5,873
Do your sources say what units/cargo was aboard…maybe cargo because three of the ships were small?

John

[fontessa]

Good morning John,

I can answer one question.

Please note in my chart that I do not show the movement of 3rd Company, 25th AAA Regiment (as you say, to Mortlock). Do you know when it travelled to the Marianas?

The 3rd Company, 25th AAA Regiment was transported by Havere Maru with the 2nd Expeditionary Unit.
- Departed Pusan on March 20
- Arrived at Yokohama on March 27
- Departed Yokohama on April 1 (?)
- Arrived at Truk on April 15
- Landed at Mortlock on May 19

fontessa

[john whitman]

Good afternoon fontessa:

Thanks for the help with the 3rd Company.

The army established three antiaircraft artillery regiments in 1942: the 24th, 25th, and 26th. Were these regiments established as completely new units with new guns and vehicles, or was each a collection of existing battalions with a new regimental headquarters?

There was a large effort in 1944 with twenty-seven regiments established. Was this because sufficient antiaircraft guns were now available? Or was it a reorganization that collected existing units into regimental formations?

I believe that some regiments like the 101st, 102nd, and 103rd at Palembang were collections and renumbering of existing antiaircraft units. Was this also true for units created in Japan?

Thanks for all your help.

John

[Wellgunde]

The Japanese were manufacturing new 75mm guns up until the end of the war. They surrendered over 4,000 artillery pieces in the 75mm range in the four home islands alone. AAA units in Japan proper were for the most part all formed from scratch. Units in outlying areas, particularly after the middle of 1944, were formed from the reorganization and reallocation of existing assets. This was true for both the Army and the Navy. The Navy was well placed from a manpower standpoint to form new units. When the war ended there were several thousand students at the Tateyama Naval Gunnery School undergoing AAA training.

[fontessa]

Good afternoon John,

The army established three antiaircraft artillery regiments in 1942: the 24th, 25th, and 26th. Were these regiments established as completely new units with new guns and vehicles, or was each a collection of existing battalions with a new regimental headquarters?

These 3 regiments were newly organized.

There was a large effort in 1944 with twenty-seven regiments established. Was this because sufficient antiaircraft guns were now available? Or was it a reorganization that collected existing units into regimental formations?
I believe that some regiments like the 101st, 102nd, and 103rd at Palembang were collections and renumbering of existing antiaircraft units. Was this also true for units created in Japan?

Most regiments were reorganized form 防空聯隊 Air Defense Regiments. The antiaircraft artillery regiments created in 1944 were mainly stationed in Japan homeland, Korea and Taiwan.
- 101st Air Defense Regiment → 101st Antiaircraft Artillery Regiment (Palembang)
- 102nd Air Defense Regiment → 102nd Antiaircraft Artillery Regiment (Palembang)
- 103rd Air Defense Regiment → 103rd Antiaircraft Artillery Regiment (Palembang)
- 67th Field Antiaircraft Artillery Battalion → 104th Antiaircraft Artillery Regiment (Pangkalanbrandan)
- 1st Air Defense Regiment → 111st Antiaircraft Artillery Regiment (Saitama prefecture)
- 2nd Air Defense Regiment → 112nd Antiaircraft Artillery Regiment (Tokyo)
- 3rd Air Defense Regiment → 113rd Antiaircraft Artillery Regiment (Kawasaki)
- 4th Air Defense Regiment → 114th Antiaircraft Artillery Regiment (Tokyo)
- 5th Air Defense Regiment → 115th Antiaircraft Artillery Regiment (Ichikawa)
- 6th Air Defense Regiment → 116th Antiaircraft Artillery Regiment (Tokyo)
- 7th Air Defense Regiment → 117th Antiaircraft Artillery Regiment (Yokohama)
- 118th Antiaircraft Artillery Regiment: Newly created (Tokyo)
- 11th Air Defense Regiment → 121st Antiaircraft Artillery Regiment (Osaka)
- 12th Air Defense Regiment → 122nd Antiaircraft Artillery Regiment (Osaka)
- 13th Air Defense Regiment → 123rd Antiaircraft Artillery Regiment (Kobe)
- 14th Air Defense Regiment → 124th Antiaircraft Artillery Regiment (Nagoya)
- 125th Antiaircraft Artillery Regiment: Newly created (Nagoya)
- 21st Air Defense Regiment → 131st Antiaircraft Artillery Regiment (Yahata)
- 22nd Air Defense Regiment → 132nd Antiaircraft Artillery Regiment (Kokura)
- 23rd Air Defense Regiment → 133rd Antiaircraft Artillery Regiment (Moji and Shimonoseki)
- 24th Air Defense Regiment → 134th Antiaircraft Artillery Regiment (Nagasaki)
- 25th Air Defense Regiment → 135th Antiaircraft Artillery Regiment (Hiroshima), Disbanded later
- 32nd Independent Antiaircraft Artillery Battalion → 141st Antiaircraft Artillery Regiment (Sapporo)
- 41st Air Defense Regiment → 151st Antiaircraft Artillery Regiment (Pusan)
- 42nd Air Defense Regiment → 152nd Antiaircraft Artillery Regiment (Soul)
- 51st Air Defense Regiment → 161st Antiaircraft Artillery Regiment (Taipei)
- 52nd Air Defense Regiment → 162nd Antiaircraft Artillery Regiment (Takao)
- 61st Air Defense Regiment → 171st Antiaircraft Artillery Regiment (Dalian)

fontessa

[john whitman]

Good afternoon fontessa:

Thanks for this information.

I am still not clear on the mobilization of regiments in 1944. Did each air defense regiment already exist before it was renumbered as an antiaircraft artillery regiment? Were some of the air defense regiments created in 1941, 1942, or 1943 and then renumbered in 1944?

John

[john whitman]

Hello again fontessa:

You mentioned that the 118th and 125th were newly created (in 1944). So all the others existed at some point before 1944?

John

[fontessa]

Good afternoon John,

- 14th Air Defense Regiment → 124th Antiaircraft Artillery Regiment (Nagoya)

I would like to correct the above as follows.
- 15th Air Defense Regiment → 124th Antiaircraft Artillery Regiment (Nagoya)

I am still not clear on the mobilization of regiments in 1944. Did each air defense regiment already exist before it was renumbered as an antiaircraft artillery regiment? Were some of the air defense regiments created in 1941, 1942, or 1943 and then renumbered in 1944?

As hisashi said, IJA antiaircraft artillery regiments had the long history. But I would like to go back to 1941. As a part of Kwantung Army Special Maneuvers, following antiaircraft regiments were mobilized in July 1941. Then these regiments were reorganized into air defense regiments in November 1941.

■ Tokyo Air Defense Unit (July) → Tobu Air Defense Brigade (November)
- Tokyo Air Defense Unit 1st Antiaircraft Artillery Regiment → 1st Air Defense Regiment
- Tokyo Air Defense Unit 2nd Antiaircraft Artillery Regiment → 2nd Air Defense Regiment
- Tokyo Air Defense Unit 3rd Antiaircraft Artillery Regiment → 3rd Air Defense Regiment
- 4th Air Defense Regiment (Newly organized in November)
- 5th Air Defense Regiment (Newly organized in November)
■ Osaka Air Defense Unit (July) → Chubu Air Defense Brigade (November)
- Osaka Air Defense Unit 1st Antiaircraft Artillery Regiment → 11th Air Defense Regiment
- Osaka Air Defense Unit 2nd Antiaircraft Artillery Regiment → 12th Air Defense Regiment
- 15th Air Defense Regiment (Newly organized in November)
■ Kokura Air Defense Unit (July) → Seibu Air Defense Brigade (November)
- Kokura Air Defense Unit 1st Antiaircraft Artillery Regiment → 21st Air Defense Regiment
- 22nd Air Defense Regiment (Newly organized in November)
- 23rd Air Defense Regiment (Newly organized in November)
- 25th Air Defense Regiment (Newly organized in November)
■ Hokubu Army
- 31st Air Defense Regiment (Newly organized in November)
■ Korea Army
- 41st Air Defense Regiment (Newly organized in November)
- 42nd Air Defense Regiment (Newly organized in November)
■ Taiwan Army
- 51st Air Defense Regiment (Newly organized in November)

Afterwards following air defense regiments were organized.
- 6th Air Defense Regiment (Tobu Air Defense Brigade, September 1942)
- 7th Air Defense Regiment (Tobu Air Defense Brigade, September 1942)
- 13rd Air Defense Regiment (Chubu Air Defense Brigade, August 1943)
- 24th Air Defense Regiment (Seibu Air Defense Brigade, August 1943)
- 52nd Air Defense Regiment (Taiwan Army, August 1943)
- 61st Air Defense Regiment (Kwantung Army, September 1942)
- 101st Air Defense Regiment (25th Army, February 1943)
- 102nd Air Defense Regiment (25th Army, February 1943)
- 103rd Air Defense Regiment (25th Army, February 1943)

Above air defense regiments were reorganized into antiaircraft regiments in 1944.

fontessa

[john whitman]

Good morning fontessa:

Thanks for this great information.

For the nine regiments organized in 1942 and 1943, were these simply new regimental headquarters placed in command of existing antiaircraft artillery battalions? Or did the Army create (eighteen?) new gun battalions and (nine? new searchlight battalions) in 1942 and 1943 along with the nine regimental headquarters? I am trying to determine how much the Army's antiaircraft force actually grew.

John