IJN Air squadrons

[geahanse]

Does any one have a list or a link of information regarding Imperial Japanese Navy squadrons in World War 2. Squadrons or wings were referred as Kokutai, correct? What about what squadrons were on what Aircraft Carriers or battleships converted for use with aircraft, with half a flight deck. I guess i just dont understand how the IJN Air Service organized their air units. The attack on Pearl Harbor for example, I have a book that says each unit was called "1st Attack Unit" , "2nd Torpedo Attack Unit" "3rd Attack Group". Im guessing the Pearl Harbor attack was organized from all the best IJN pilots but what about other times in the war? A list of all the squadrons and date of formation would be greatly appreciated as well.

[LWD]

If you don't get an answer here pretty soon try asking at:
http://www.j-aircraft.org/smf/index.php?board=3.0

[Wellgunde]

This is a huge topic. There were something like a total of 90-100 Kokutai organized during the war. The Second Demobilization Bureau's post war (very brief) summary of the establishment, disestablishment, assignment and transition of Imperial Japanese Navy air units runs over one hundred pages (unfortunately in Japanese).

For a good introduction, I suggest you consult The Japanese Air Forces in World War II, Arms and Armour Press, 1979. This is a reprint of a late 1945 British War Office intelligence publication. Despite being an intelligence document with all the caveats that entails, the information in this book is very reliable. Used copies from Amazon.com and Abebooks.com start at around $30 each.

Wellgunde

[steverodgers801]

Each carrier had units attached to it, unlike America which could shuttle air units between carriers. You also need to divide the IJN air arm before and after Midway.

[geahanse]

I just did some research about the carrier groups and learned that yes, each carrier had its own groups that stayed with them and had the title of the carrier of which they were on, for example Air Group Shōkaku and Akagi Aircraft Group. The only list I found is:

https://en.m.wikipedia.org/wiki/List_of ... anese_Navy

It lists quite a few groups but I'm trying to find a little bit more information regarding details of the Air Groups such as their service record and what campaigns they fought in. Maybe their isn't that sort of information on the Internet and I don't want to spend money on ordering a book if there happens to be that information on the Web. This topic is similar to trying to research information on Soviet Air Regiments of World War 2, what very little information there is, is in Russian, or in this case most likely Japanese

[hisashi]

My old post might be a starting point.
Dai,Chu,Sho and Tai: A Japanese guide for unit size
http://forum.axishistory.com/viewtopic.php?f=65&t=29623

I wrote navy aviation squadron was hikotai. It was true for ground-based navy air force, but in a carrier, hikotai often meant whole aircrafts on the ship, such as 'Akagi hikotai'.

According to JACAR C13071996500, In the latest authorized personnel chart in 30 Jun 1941, CV Akagi had
1 Hikocho, Cmdr.
5 Hikotaicho, Cmdr. or Lt.Cmdr.
12 Buntaicho (for aviation/aviation staff), Lt.Cmdr. or Leut.
12 line officers (for aviation/aviation staff), Ensign, 2nd Leut. or Leut.
22 aviation officers, Ensign, 2nd Leut. or Leut.
33 aviation warrant officers
145 aviation petty officers

I omitted maintenance crew, so 'aviation staff' means here backline staff works for aircrafts and crews.

Hikocho was a staff reporting to the skipper. We know Cmdr.Fuchida was THE Hikotaicho of CV Akagi at Pearl Harbor. So apparently IJN used these posts for senior aviation officers but did not call them as Hikotaicho.

They made up 'squadrons for today's sortie' seeing crews' health and status of each machine. So squadron (hiko chutai) leader could not be permanent, though assigned among buntaicho officers. Again perhaps, hikotaicho posts were used for the leader of each division (dive bomber, fighter etc.). Seeing combat report, a hiko chutai was typically 9 pieces for fighters, varying from 5 to 12 for attackers/bombers.

I usually call kokutai as a naval air group using terminology by Leo Nieholster.
http://www.niehorster.orbat.com/014_jap ... /_ijn.html


Preparing the battle, known as Battle of the Philippine Sea, IJN raised 601st naval air group (dai 601 kokutai) in Feb 1944. It included all aircrafts on CV Shokaku, Zuikaku and Taiho. Similarly 652nd NAG was organized for CVL Junyo, Hiyo and Ryuho, and 653rd for CVL Chitose, Chiyoda and Zuiho in Feb-Mar 1944.

http://en.wikipedia.org/wiki/Battle_of_ ... ippine_Sea

So this battle was the only occasion in which IJN carrier air force was formally organized across CVs.
OoB for this battle was hard to understand because Ozawa occupied three posts concurrently. Ozawa's main force was 3rd fleet, including CV Shokaku, Zuikaku, Taiho, CVL Junyo, Hiyo and Ryuho. Kurita's 2nd fleet, including CVL Chitose, Chiyoda and Zuiho was a vanguard of the 3rd fleet.

1st Mobile Fleet was a fleet on paper. Both the commander and chief in staff was the same as 3rd fleet. It was a bureaucratic assignment so that Ozawa could direct Kurita. Also, Ozawa on CV Taiho led 1st air (or carrier) squadron. Also on paper, 601st NAG reported to 3rd fleet CO, namely Ozawa leaping any CV skipper.

At Pearl Harbor they needed other device for unified command of carrier air forces because each carrier hikotaicho reported to his skipper. They appointed Fuchida as a staff for Nagumo (CO, 1st air fleet including 6 CVs) and Fuchida led all air forces by the authority of fleet commander. So it's why you cannot find any order of battle showing aircraft command structure for this battle.

battleships converted for use with aircraft, with half a flight deck

IJN prepared 634th NAG for BB Ise and Hyuga but eventually IJN used them in Philippine as a seaplane group before Ise and Hyuga made their last sortie.

[ijnfleetadmiral]

I've got info on various air groups, such as COs and so forth. If you're interested, PM me with your email and I'll send you what I have.

[PTO Researcher]

The best source on this topic I've found is the 8 volume series called "Beyond the Sky" published between 2009 and 2012. It unfortunately is in Japanese but copies (subject to somewhat restrictive copywrite restrictions) are available from the National Diet Library in Japan (https://www.ndl.go.jp/en/). I have downloaded the table of contents of each volume from the volume-specific descriptions and translated the TOCs into English (no Japanese language skills so heavy use of on-line translation tools). There were approximately 297 distinct Naval Air Groups formed between 1916 and 1945 (including all training units but not including the pre-2/44 carrier-based units which were directly assigned to the carriers) and 81 hikō-tai units (formed from 3/4/44 through the end of the war).

Links to the first 4 volumes of this series which cover all the naval air groups and the hikō-tai are as follows:

https://rnavi.ndl.go.jp/mokuji_html/000010659682.html
https://rnavi.ndl.go.jp/mokuji_html/000010589018.html
https://rnavi.ndl.go.jp/mokuji_html/000010589022.html
https://rnavi.ndl.go.jp/mokuji_html/000010589024.html

I believe that the pre-2/44 carrier-based air units are included in a separate multi-volume series on Japanese naval units by the same author.

The best source I've found for Japanese naval unit organization (including all of the air units) for the 12/7/44-8/15/45 period is JM-116.

https://ww2db.com/other.php?other_id=15

[fontessa]

The best source on this topic I've found is the 8 volume series called "Beyond the Sky" published between 2009 and 2012. It unfortunately is in Japanese but copies (subject to somewhat restrictive copywrite restrictions) are available from the National Diet Library in Japan (https://www.ndl.go.jp/en/). I have downloaded the table of contents of each volume from the volume-specific descriptions and translated the TOCs into English (no Japanese language skills so heavy use of on-line translation tools). There were approximately 297 distinct Naval Air Groups formed between 1916 and 1945 (including all training units but not including the pre-2/44 carrier-based units which were directly assigned to the carriers) and 81 hikō-tai units (formed from 3/4/44 through the end of the war).

Links to the first 4 volumes of this series which cover all the naval air groups and the hikō-tai are as follows:

https://rnavi.ndl.go.jp/mokuji_html/000010659682.html
https://rnavi.ndl.go.jp/mokuji_html/000010589018.html
https://rnavi.ndl.go.jp/mokuji_html/000010589022.html
https://rnavi.ndl.go.jp/mokuji_html/000010589024.html

I believe that the pre-2/44 carrier-based air units are included in a separate multi-volume series on Japanese naval units by the same author.

They are "渡辺博史 空の彼方 Beyond the Sky" edited by Watanabe Hiroshi. He investigated IJN's TROMs for many years and self-published the results. He donated them to three libraries. We can only see his TROMs there in Tokyo.
- 国会図書館 National Diet Library
- 防衛研究所図書館 National Institute for Defense Studies Library
- 靖国神社靖国偕行文庫 Yasukuni Shrine Yasukuni Kaiko Library


The below shows his TROMs.It should be noted that these are "TROMs" - although more detailed than the Web Page "NIHON KAIUN”’s TROMs. In other words, they refer only to the movements and personnel of IJN ships, fleets, and units, but not their compositions.

"Beyond the Sky"

渡辺博史 0.jpg (72.91 KiB) Viewed 1334 times

"Surface Ships and Their Units"

"Aircraft Carriers, Their Units and Air Units"

"Submarines and Their Units"

渡辺博史 3.jpg (98.61 KiB) Viewed 1334 times

The best source I've found for Japanese naval unit organization (including all of the air units) for the 12/7/44-8/15/45 period is JM-116.

We can see the source of JM-116 in “国会図書館デジタルコレクション National Diet Library Digital Collection” which was prepared by 第2復員局 2nd Demobilization Bureau in 1949;
https://dl.ndl.go.jp/pid/8815634/1/1

fontessa

[ijnfleetadmiral]

I wonder if they would have some of the officers I'm missing from my records (ex: KISO's Torpedo Officers after 15 November 1940)...

[roberto machella]

Good morning
English translation Japanese initials
Thank you
Roberto Machella
Italy

[roberto machella]

JM-116

[PTO Researcher]

Thanks for clarifying Fontessa. For my purposes, the TROMs for the Naval Air Groups are one of the key things I'm looking for. The other being the unit compositions (aircraft by type and quantity) which I can generally piece together for most units from other sources. But, would be nice if everything was in one place.

[PTO Researcher]

If anyone wants the complete list of IJN naval air groups (1916-1945) and hikotai (1944-1945) including dates when these units were active please message me and I can forward a spreadsheet. If I get too many requests I'll see if I can publish it and provide a link. My source is the translated table of contents from the Japanese language Beyond the Sky series. As Fontessa mentions, this is a TROM for the air units similar to the TROM published on the Nihon Kaigun web site for the naval units. I have copies of portions of Volume 7 covering Japanese Navy construction units and can verify this source is the real deal.

The Wikipedia link for IJN air groups, carrier air groups (pre-2/44 and post-2/44) and seaplane tender groups is as follows: https://en.wikipedia.org/wiki/List_of_a ... anese_Navy

There are some minor variations between the Wikipedia link (it does not list the Hikotai formed in 1944-45 for example which the Beyond the Sky series does) but it does list the aircraft carrier and seaplane groups. Fontessa listed the 4 volume series on Aircraft Carriers, Their Units and Air Units and I'm in the process of trying to find the table of contents for this series on NDL and will translate it once I find it and add it to my spreadsheet.

In combination, this should cover all Japanese Navy air units during World War 2 with the possible exception of float planes on capital ships.

[PTO Researcher]

Well, that wasn't hard. Here's the links to the 4-volume series on the IJN Aircraft Carriers, Their Units and Air Units:

https://ndlonline.ndl.go.jp/#!/detail/R ... 4096205-00
https://ndlonline.ndl.go.jp/#!/detail/R ... 4760331-00
https://ndlonline.ndl.go.jp/#!/detail/R ... 5089904-00
https://ndlonline.ndl.go.jp/#!/detail/R ... 5089988-00