Pre- war intelligence

Over time, I’ve read much of the literature pertaining to the Japanese decision to initiate hostilities against the United States by launching a preemptive strike against the American fleet (and facilities) at Pearl Harbor. I believe that one factor that contributed to the tactical success of the Japanese attack was the failure of American intelligence to focus on the ‘capabilities’ of the Japanese, particularly their ability to conduct multi- carrier operations.
Here’s my question: Has anyone seen a comprehensive study of the information available to US intelligence prior to December 1941 which should have indicated that the advances made in Japanese tactics, techniques, and procedures increased the capabilities of the Kido Butai to the level that brought strike aircraft within attack range of Pearl Harbor on 7 Dec 1941? I’ve read a few “Oh, by the way”, comments to the effect that the Navy didn’t believe that the Japanese planes- nor their pilots- were very good, etc. but I’ve wondered if there exists any real pre-war analysis that gives a clear picture of what the US, particularly the US Navy, believed about the capabilities of the Imperial Japanese Navy, especially in the capabilities of naval aviation, and the information that supported this perception?
NOTE: I’m basically familiar with MAGIC, the 14 part message, etc. No need to go that direction.

 

Yes, the Bulletins, summaries, and estimates cited above are 'starter info'. But, intelligence is not synonymous with information.
Let me give you an example:

September 17, 1941
Memorandum for the Assistant Chief of Staff, W. P. D.:
Subject: Combat Estimate, Japan. (With map showing disposition armed
forces.

TAB A-COMBAT ESTIMATE, JAPAN​

"The Japanese naval personnel is well trained-equal to that of the British and American navies. The Japanese navy is modern, well balanced, and ready for prompt service. It is relatively strong in aircraft carriers and tenders; it would be a formidable opponent to the navy of any power or those of any combination of powers attempting offensive operations in the western Pacific area. "

Seems to be very good 'intel' as the events of the subsequent years proves. But, what 'information' led to this conclusion? Did any 'information' relate to the emerging ability of the Japanese carrier forces to coordinate multi- carrier attacks? Clearly, the Kido Butai demonstrated the capability to launch a simultaneous, coordinated attack from six aircraft carriers in December, 1941; the US Navy was clearly not able to launch a coordinated strike from three carriers in June, 1942- in fact, at Midway, only the YORKTOWN was able to coordinate it's own fighters, torpedo bombers, and scout and dive bomers.
My 'gut feel' is that Japanese strengths were evaluated in terms of US Navy doctrine that existed at the time. Was any 'information' available in, say, 1941 concerning specific training in tactics, techniques, procedures that might have led to an 'imaginative' intel asking:' Why are the Japanese carrier forces training together'? 'If they become proficient in having 4 carriers attack the same target at the same time, how and where could they use this capability'?
What I'm asking is: Do you know if anyone has studied the information that went in to the intelligence cycle that produced summaries and estimates such as those cited above?
(What did they know? When did they know it? How did they interpret it?)

 

Try Combined Fleet Decoded – it might have specific information. US naval intelligence did identify Nagumo’s 1st Air Fleet and its OOB long before war. The problem was that in most other cases in the Japanese navy, this type of command was administrative in nature, not operational. For example, 2nd Fleet’s OOB included 13 heavy cruisers, which during operations were parcelled out to different operational commands. The assumption was that 1st Air Fleet’s organization and intended deployment pattern would be the same.

 

"The assumption was that 1st Air Fleet’s organization and intended deployment pattern would be the same."

A long time ago, I was told that 'assume' could be pronounced as 'ass- YOU and ME'.

And, that,when using an 'assumption' to form a conclusion, you should explicitly state: 'Assuming that the 1st Air Fleet is just administrative in nature, it is probable that each CarDiv will will be assigned to different operational commands.' or something like that.

So, any indication that there was any 'information' that would have led to an 'assumption' that the Japanese were moving toward employing four or six carriers as an operational command vice an administrative command?

I read Combined Fleet Decoded - can't remember if there was anything that would help.

 

Isnt "assuming" (as much as they probably hate to do that) what Intellegence services do? They are shooting in the dark sometimes with scraps of information. I would think assuming or guessing is the band-aid to come to conclusions. Unfortunately, its not always correct. We assumed the Japanese would strike the Philipeans and the South Pacific instead of Pearl. That was used with assuming and just common sense in regards to the thinking at the time.

 

I don’t want to turn this topic into a “What were some of the assumptions that doomed battle plans?” (Yamamoto at Midway; Montgomery and Market- Garden, MacArthur and the defense of the Philippines or MacArthur and the Advance to the Yalu- well, not the last two- the god- like Douglas was never ever wrong .) What I’m trying to nail done is to see if anyone examined the possibility that there were other sources (in addition to MAGIC and radio traffic analysis) of information available to US Intelligence that reinforced (or could have contradicted) certain pre- existing assumptions about how Japan would conduct major hostilities.
I agree that “assuming and just common sense” would lead to the conclusion that the Japanese needed to secure raw materials from Southeast Asia and the Dutch East Indies (oil, rubber, etc) and that Japan would have to neutralize American and British bases and territories such as the Philippines, Singapore, Guam, etc. But was it “just common sense” that therefore the Japanese would commit the majority of their naval power to the south and then turn to face the American fleet steaming across the Pacific in a ‘decisive battle’?
Did any information exist that might have led to a different analytical path? Suppose that Naval Intelligence had learned in the late summer that 1st Air Fleet Air Groups were training over Kyushu, especially near Kagoshima City. Japanese planes were observed climbing over a 5000 ft mountain, diving down into the city, dropping torpedoes aimed at a breakwater? Naval Intelligence knew about the Brits’ use of torpedoes in the attack against Italian ships in Taranto. Would a logical assumption be that the Japanese were training to use a large portion of their carrier aviation against an enemy (American or British) port? Singapore? Manila Bay? What about Pearl Harbor? I realize that this was in the time before spy satellites, SR-71s, U-2s, etc and it was unlikely that any of our military attaches in Japan would be invited to watch the ‘maneuvers’. Perhaps some sharp analyst would have asked: ‘If the Japanese do intend to use these tactics to attack Pearl Harbor, what else would have to happen for them to be successful? Surprise by getting as close as possible without being detected? ? Attack when a large number of ships would be tied up in the harbor?
To sum it up, I’m looking for research that lays out how the information that has been examined (especially in all the ‘who shot John’ investigations and the ‘conspiracy’ literature) numerous times was used to develop the intelligence that was disseminated in the days and weeks prior to Dec 7/8 1941 and to determine if there is any other information that exists but hasn’t received the same scrutiny.

 

"I've been looking for the same thing since 1965. Let me know if you find anything."

Sure will. But, I'm not sure it's out there, for the reasons you pointed out.
Thanks for the discussion.

 

As to studies done US military intelligence, I have not heard of any. Much of the information gathered came in bits and pieces.

For instance, Claire Chennault sent reports and warnings about the Japanese Zero back to the US in mid-1941. However, most dismissed his reports as exaggerated, while a few tool them to heart. Naval pilot John Thach credited Chennault's warnings with prompting him to come up with new tactics and techniques for fighting the new Japanese aircraft.("Fire in the Sky" by Eric M. Bergerud, pg 450-51)

The US also had a good idea of the capabilities of Japanese ships, but not their torpedoes.

Still, on the other hand, one might say that it was that the Americans knew the Japanese capabilities too well. The Americans knew that most of the Japanese warships could not reach Pearl without being refueled. They also knew that the Japanese, for the most part, had never conducted underway refueling exercises. While true, the Japanese did successfully experiment with underway refueling of their large ships some two months before launching their attack on Pearl Harbor. Another fact which would most certainly have escaped American intelligence was the fact that to extend the range of the carriers Akagi, Hiryu, & Soryu, as well as the heavy cruisers Tone and Chikuma, the Japanese had crammed drums of extra fuel oil into every available space aboard these five ships.

Another factor in the surprise would be the belief held by many in the US military forces and civilian leadership that Japan would not be so foolish as to attack the US, a nation she could not hope to defeat in war(IIRC, Prange mentions this several times, as does Willmott). The US Admirals and Generals were well aware of the economic disparity between the two nations and that the US was rapidly rearming her military, and thus fully confident that if Japan decided to start a war the US could handily defeat her.

So, even with mostly "up to date" information on Japanese planes and ships, the Americans will still "get caught with their pants down" on December 7, 1941.

 

In hindsight of course, this mentality seems almost incredible considering that Japan had been aggressive since 1931.

But then again, the affects of the depression, Japan being so far away, bigoted attitudes possibly......

 

Gotcha! You said you have not heard about any U.S. agents in Japan.

Have you come across anything (that is not classified) from any other countries' services?

Russia for example?

As good as the NKVD was at plotting agents, and Japan and Russia's history with each other, I would think the Russians would be keeping an eye on the IJN.

 

Nice! I need to look him up tonight in my KGB books I just bought.

I don't know much about this source btw, but spymuseum.com stated this in a quick bio:

The blurb also states he came to the US and had some meetings with communist leaders. I wonder if he was allowed to say anything? Probably not, but I am a little intrigued now.

 

About the only thing I can think off the top that might have pointed that way was the communications chatter made by Kido Butai pilots during training in the fall of 1941 as they ramped up for Pearl. IIRC, different units were training at different bases, but at some as many as four carriers were contributing to the program. If true (and I don’t know it is) then it is possible a savvy intelligence type might have pegged four carriers contributing aircraft to one formation and said, ‘hey what if...’.

Whoever told you that should sit down and play a few wargames, where he will soon discover that assumptions are fundamental to action planning and that hindsight to errors is 20/20.

I think the Hypo logs and other raw working sources are still classified to this day. This is because in an unrelated matter, Isom and the authors of Shattered Sword got into it over a HYPO summary at Midway, in which Isom mentioned in passing that the original working sheet from which the 1945 summary was extracted remained classified. Why this would be so is open to speculation, but it cannot be due to national security or any other such fluff. Other material, such as passive intercept logs from the Alaskan command – these might or might not be classified, but scattered to the four winds.

 

ULITHI,

Sorge was GRU, not KGB.