Pearl Harbor advance-knowledge debate

From Wikipedia, the free encyclopedia

Ever since the Japanese attack on Pearl Harbor on December 7, 1941, there has been much debate as to how and why the United States had been caught unaware, and how much and when American officials knew of Japanese plans and related topics. Several writers, including journalist Robert Stinnett and former United States rear admiral Robert Alfred Theobald, have argued various parties high in the US and British governments knew of the attack in advance and may even have let it happen or encouraged it in order to force America into war via the so-called "back door." Evidence supporting this view is taken from quotations and source documents from the time and the release of newer materials.

Part of the controversy of the debate centers on the state of documents pertaining to the attack. Just as there are records from WWI that remain sealed, there are some related to Pearl Harbor which have not been made public. Others may not exist, as many documents were destroyed early during the war due to fears of an impending Japanese invasion of the Hawaiian Islands, still others are partial and crudely mutilated.^[1]

Examination of information released since the War has revealed there was considerable intelligence information available to US and other nations' officials. It may have been the failure to process and use this information effectively that has led some to invoke conspiracy theories rather than a less interesting mix of mistake and circumstance. The US government had nine official, and yet none totally accepted as definitive, inquiries into the attack – the inquiry by Secretary of the Navy Knox (1941), the Roberts Commission (1941–42), the Hart Inquiry (1944), the Army Pearl Harbor Board (1944), the Naval Court of Inquiry (1944), the Hewitt investigation, the Clarke investigation, the Congressional Inquiry (1945–46) and the top-secret inquiry by Secretary Stimson authorized by Congress and carried out by Henry Clausen (the Clausen Inquiry) (1946).

It is important to note investigators prior to Clausen did not have the security clearance necessary to receive the most sensitive information and some of those questioned were put in a difficult spot of having to lie (even under oath) to protect secrets they were charged with. Clausen reported even though he had a letter from Secretary Stimson informing witnesses he had the necessary clearances to require their cooperation, he was repeatedly lied to until he produced copies of top secret decrypts, thus proving he indeed had the proper clearance.

The information Clausen collected was not declassified until the mid-1980s and not published until 1992, when Clausen wrote his own account of the investigation.

Contents 1 Had the US broken Japanese military codes before the attack? 2 Was the Kido Butai broadcasting? 3 Circumstantial evidence 3.1 High-ranking officials 3.2 Japanese intelligence 3.3 Grid planning 3.4 Allied intelligence 3.5 Advance warning and code breaking 3.6 American carriers 3.7 American immediate reaction 3.8 War with Germany 4 Controversy 5 Some remaining classified materials relating to Pearl Harbor 6 Notes 7 Further reading 8 External links

[edit] Had the US broken Japanese military codes before the attack?

The JN-25 code is one of the most debated portions of Pearl Harbor lore. JN-25 is the US Navy's final term for the cryptosystem the Imperial Japanese Navy sometimes referred to as Naval Code D. Other names used for it include five-numeral, 5Num, five-digit, five-figure, AN, and AN-1, and so on. It was an example of the then state of the art in cyphers and is quite different than modern forms of message encryption in being a code (ie, battleship = 63982) and further being superencrypted with an additive cypher, also from a distributed book. It was based upon the Latin alphabet, due to the difficulties in using Japanese writing. Superencrypted codes of this sort were widely used and can be considered the state of the art in practical military cryptography of the time. It should be noted this code is very similar in principle to the British "Naval Cypher No. 3", known to have been broken by Germany during WWII.^[2]

Once it was realized what sort of cryptosystem JN-25 was, the cryptanalytic approach was known. Stinnett in fact, notes the existence of a handbook for attacks on such codes produced by OP-20-G. That said, breaking it was not easy. It took much effort and time, not least in accumulating sufficient depth prior to the outbreak of hostilities when IJN radio traffic increased abruptly and substantially; prior to 7.12.41 IJN radio traffic was very limited, as most Japanese encrypted broadcast military radio traffic was Army traffic associated with the land operations in China. The chief approach is related to cryptanalytic attacks used as long ago as early in the 19th century ((Scovill's analysis survives from Wellington's Peninsular Campaign).^{[citation needed]}

The original JN-25A system replaced the 'Blue' code (as Americans called it), and used five-digit numbers, each divisible by three (and so usable as a quick, and somewhat reliable, error check, as well as a 'crib' to cryptanalysts), giving a total of 33,334 valid code values. To make it harder to crack a code value, 'noise' was overlaid into transmitted messages in the form of meaningless additives (from a large table/book of five-digit numbers), to obscure the code values. JN-25B superseded the first release of JN-25 at the start of December of 1940. JN-25B had 55,000 valid codes and while it initially used the same additive list, this was soon changed and the code breakers found themselves back to square one.

Over the years, various claims have been made as to the progress made decrypting this systems, and arguemnts over when it was readable (in whole or part). Lt. "Honest John" Leitweiler, Commander of Station CAST, the Philippines, stated in November of 1941 his staff could “walk right across” the number columns of the coded messages. He is frequently quoted in support of claims that JN-25 was then mostly readable. This comment, however, refers not to the message itself but to the superencrypting additives and referred to the ease of attacking the code using a new method for discovery of additive values.

A couple of often cited claims of code breaking are: A 16 November 1941 letter (Navy Department, Philippines Operations Summaries, 3200/1-NSRS) to L.W. Parks (OP-20-GY) sent by Leitweiler, "We have stopped work on the period 1 February to 31 July as we have all we can do to keep up with the current period. We are reading enough current traffic to keep two translators very busy." Another exhibit No. 151 from the Hewitt Inquiry has a copy of the US Navy message OPNAV-242239 'Evaluation of Messages of 26 November 1941' which has in part: '1. Reference (a) advised that Com 16 intercepts were considered most reliable and requested Com 16 to evaluate reports on Japanese naval movements and send despatch to OPNAV, info CINCPAC. Com 16's estimates were more reliable than Com 14's, not only because of better radio interception, but because Com 16 was currently reading messages in the Japanese Fleet Cryptographic System ("5-number code" or "JN25") and was exchanging technical information and translations with the British C. I. Unit at Singapore. McCollum knew this and gave it due consideration when he drafted reference (a).' Whitlock, also at the time, was not even aware the IJN movement traffic code was being read.

However, reading here means being able to see the underlying code groups, not breaking out the messages into plain text. [1] Futher reading from the same Hewitt Inquiry document also states "The "5 numeral system" (JN-25B) yielded no information which would arouse even a suspicion of the Pearl Harbor raid, either before or afterward"

Additionally, no decrypts have come to light of JN-25B traffic with any intelligence value prior to Pearl Harbor. Such breaks as recorded by Holmes and Blair were into the additive tables, which was a required first step of two. The first 100 JN-25 decrypts from all sources in date/time order of translation have been released, and are available in the National Archives. The first JN-25B decrypt was in fact by Station HYPO (Hawaii) on 8 January 1942 (numbered #1 up JN-25B RG38 CNSG Library, Box 22, 3222/82 NA CP). The first 25 decrypts were very short messages or partial decrypts of marginal intelligence value. As Duane Whitlock stated, "The reason that not one single JN-25 decrypt made prior to Pearl Harbor has ever been found or declassified is not due to any insidious cover-up...it is due quite simply to the fact that no such decrypt ever existed. It simply was not within the realm of our combined cryptologic capability to produce a usable decrypt at that particular juncture."

Notwithstanding the above, a statement by Vice Admiral Frank E. Beatty (USN retired) about the pre-Pearl Harbor Japanese "Nanshin" fleet movement to the south, from his article “Background of the Secret Report,” National Review, December 13, 1966, page 1261, has: “… When the Japanese Task Force emerged from Kamranh, it was shadowed and trailed by our submarines, so Washington was alerted as to the composition, course, and speed of this group of vessels. In addition, through our breaking of the Japanese codes, we were alerted as the destination of this particular group, it being known that the ships were headed for the KRA Peninsula, Khota Baru, their destination, was also broken out of code. ..." That is, " ... our breaking ..." of Japanese operational naval codes ... yielding specific intelligence.

Detailed month by month progress reports have shown no reason to believe any JN-25B messages were fully decrypted before the start of the war. Tallied results for September, October, and November reveal roughly 3,800 code groups (out of 55,000, about 7%) had been recovered by the time of the attack on Pearl Harbor.

US signals intelligence in 1941 was both impressively advanced and uneven. The US MI-8 cryptographic operation in New York City had been shut down by Henry Stimson (Hoover's newly appointed Secretary of State), which inspired its now broke former director, Herbert Yardley, to write a book (The American Black Chamber) about its successes in breaking other nations' crypto traffic. Most countries responded promptly by changing (and generally improving) their ciphers and codes, forcing other nations to start over in reading their signals. The Japanese were no exception. Nevertheless, US cryptanalytic work continued after Stimson's action in two separate efforts: the Army's Signal Intelligence Service (SIS) and the Navy's Office of Naval Intelligence (ONI) crypto group, OP-20-G. Cryptanalytic work was kept secret to such an extent, however, that commands such as the 14th Naval District at Pearl Harbor were prohibited from working on code breaking by Admiral Kelly Turner as a consequence of the beaucratic infighting in Washington. In any case, the eventual flow of intercepted and decrypted information was tightly and capriciously controlled to the point that at times even President Roosevelt did not receive information from code-breaking activities. (This was in part due to fears of compromise as a result of poor security, after decrypts were found in the wastebasket of one of his advisors.^{[citation needed]})

By late 1941, those organizations had broken several Japanese ciphers (such as "PA-K2", called Tsu by Japan, and the highest security diplomatic code, dubbed "PURPLE" by the U.S.), but had made little progress against the current Naval JN-25 code.

The break into the PURPLE cipher was a considerable cryptographic triumph, and proved quite useful later in the War. It was the highest security Japanese Foreign Office system, but prior to Pearl Harbor carried little information about Japanese plans; the military, who were essentially determining foreign policy for Japan, distrusted the Foreign Office and left it "out of the loop". And unfortunately for the US, the two US crypto groups generally competed rather than cooperated, and distribution of intelligence from the military to US civilian policy-level officials was poorly done (eg, capriciously selected for distribution) by both the Army and Navy who handled the traffic on alternate days, and furthermore in a way that prevented any of its recipients from developing a larger sense of the meaning of the decrypts. Along with the over-reactive obsession with security, there was little or no analysis done for receipients. Decrypts were typically provided raw, completely without context, and without much taking into account the needs of the receipients. As well, the recipients were not permitted to retain them, or notes made from them, again for security reasons.

In addition, there was a perennial shortage of manpower, thanks to penury on one hand and the perception of intelligence as a low-value career path on the other. Translators were over-worked, cryptanalysts in short supply, staff generally stressed. Furthermore, there were difficulties retaining good intelligence officers and trained linguists; most did not remain on the job for the extended periods necessary to become truly professional. For career reasons, nearly all wanted to return to more standard assignments.

The US was also given decrypted messages by Dutch (NEI) intelligence, who like the others in the British-Dutch-US agreement to share the cryptographic load, shared information with allies. The U.S. refused to do likewise.^[3]

[edit] Was the Kido Butai broadcasting?

As the Kido Butai (Special Attack Force), led by Admiral Chuichi Nagumo, neared Hawaii, there is claimed to have been a flurry of radio traffic that begat warnings to US intelligence and even directly to those with White House connections. For instance, the Matson liner SS Lurline, heading from San Francisco to Hawaii on its regular route, is said to have heard and plotted unusual radio traffic, noting that telegraph code used was very different from International Morse. That traffic, which is said to have persisted for several days, and noted as coming from a moving source and not shore stations, is further claimed by some to have been from the approaching Japanese fleet.

There are several problems with this analysis. Surviving officers from Nagumo's ships state there was no radio traffic to have been overheard by anyone; their radio operators had been left in Japan to fake traffic for the benefit of listeners (ie, military intelligence traffic analysts in other countries), and all radio transmitters aboard Nagumo's ships were physically disabled to prevent inadvertent broadcast and subsequent tracking of the attack force. Note also, this is to some extent contradicted by Layton.^[4]

To disobey the radio silence orders would mean that the location of the entire attack force might have been exposed; the personnel reports fit well with the requirements of the objective situation. Unfortunately, the current whereabouts of either Lurline's log, or the reports delivered to the Navy by Lurline's radio operator Leslie Grogan in Hawaii, are not known, so contemporaneously written evidence of what was recorded aboard Lurline is not now available - the original logs Lurline surrendered (to the USN?) in Honolulu have gone walk-about. Generally, however, the directions given by Grogan in a recreation of the logbook for the Matson Line are consistent with locations used for radio deception by the Japanese (from the homeland) at the time. A recently discovered missing report by Leslie Grogan, dated Dec. 10 1941 and titled "Record for Posterity", also does not support claims of Kido Butai broadcasting.

One suggested example of a Kido Butai transmission is the November 30, 1941 COMSUM14 report in which Captain Joseph Rochefort of Hawaii's code-breaking Station Hypo mentioned a "tactical" circuit was heard calling "marus" (a term for commercial vessels or non-combat units; SHIRIYA MARU, an IJN tanker and not a member of Japan's merchant fleet, appears in Parts XIII, pages 407, 420, 462-464, and Part XXX, page 2743, 2787, and 2792 in the Hearing before the Joint Committee; further, message SRN-116476 refers to two "marus" - so the usage was not definitive). Rochefort's reference is to routine housekeeping traffic, part of the extensive IJN radio deception program to mislead enemy intelligence into believing the units and commands of the Kido Butai were continuing to exercise off Kyūshū and the Western Inland Sea.

Of note, for added clarity here, the perspective of US naval intelligence at the time as taken from the Proceedings of the Hewitt Inquiry (on page 515) shows: " ... The significance of the term, 'tactical circuit' is that the vessel itself, that is AKAGI, was using its own radio to call up and work directly the other vessels rather than work them through shore stations via the broadcast method which was the common practice in Japanese communications. The working of the AKAGI with the Marus, indicated that she was making arrangements for fuel or some administrative function, since a carrier would rarely address a Maru." [N.B., ... making arrangements for fuel ...]

As given by IJN Admiral Toimioka,^[5], the oilers supporting the Kido Butai are: Kyokuto Maru, Kenyo Maru, Kokuyo Maru, Shinkoku Maru, Toho Maru, Nihon Maru, Toei Maru, and Shiriya. Prange also<refibid., page 435</ref>, regarding HIJMS 'Shiriya, has "... naval unit designed as an auxiliary to the Pearl Harbor task force ... The skipper of Shiriya was Captain Minour Togo, son of the great Admiral Heihachiro Togo. ..."^[6]{fact}

[edit] Circumstantial evidence

[edit] High-ranking officials

One quote from Gordon Prange's Pearl Harbor: The Verdict of History is often used to add legitimacy to the notion the British Government knew in advance that the attack was coming. Oliver Lyttelton, the British Minister of War Production, is quoted on page 35 as saying, " ... Japan was provoked into attacking the Americans at Pearl Harbor. It is a travesty of history ever to say that America was forced into the war. Everyone knows where American sympathies were. It is incorrect to say that America was truly neutral even before America came into the war on an all-out basis."

When considering information like this as a point for or against, the reader must keep in mind questions such as: was this official privy to information about the US government? did he have communications with high-level administration figures such as President Roosevelt or Ambassador Grew? or is this just a strongly held personal opinion?

For instance, one position discussed in author Robert Stinnet's book Day of Deceit suggests a memorandum prepared by Office of Naval Intelligence Lieutenant Commander Arthur McCollum was central to US Government policy in the immediate pre-war period. The memo suggests only a direct attack on US interests would sway the American public to favor direct involvement in the European war, specifically in support of the British.

Although the memo was passed to Captains Walter Anderson and Dudley Knox, two of Roosevelt's military advisors on October 7, 1940, there is no evidence available to suggest Roosevelt ever saw it, nor can it be proved he did not. Moreover, although Anderson and Knox offered eight specific plans to aggrieve the Japanese Empire and added, "If by these means Japan could be led to commit an overt act of war, so much the better," of the eight "plans" (actions to be taken) offered in the memo only one was ever implemented in any fashion, and there is considerable doubt the memo was the inspiration. Nonetheless, as shown in the Notes section of Stinnett's "Day of Deceit" (paperback edition) for Chapter Two (FDR's Back Door to War), pages 321-322, are notes 7, 8, and 11 which show in fact all action items were indeed implemented.

ONI, in Washington, is further said to have been aware of Japanese carrier movements. First publicly reported in John Toland’s Infamy, was a Dutch Rear Admiral's claim to have been present at the US Office of Naval Intelligence not long before the 7th. According to Toland, and perhaps entries in J.E. Meijer Ranneft’s diary made on December 2nd and on December 6th, ONI informed Ranneft about two Japanese carriers. Toland claims the diary states these ships were northwest of Honolulu. Later, Toland claims the diary states the ships were north. However, among other problems with the story, the diary (photo in hardback version, removed in later paperback printings) states “beW. Honolulu.” meaning “Westerly of”. Also none of the witnesses present on those dates support Ranneft’s claims, clouding their actual significance considerably. Some speculate the diary could have been reference to carriers near the Marshall Islands. Toland has also made other conflicting and incorrect claims about the diary as well.

[edit] Japanese intelligence

Japanese intelligence (that is, espionage) efforts against Pearl Harbor included at least two German Abwehr agents. One of them, Otto Kuhn, was a sleeper agent living in Hawaii with his family; he and they were essentially incompetent. The other, Dusko Popov, a Yugoslavian businessman, was thought quite effective by Abwehr, but was actually a double agent whose loyalty was to the British. He worked for the XX Committee of MI5. In August 1941 he was tasked by Abwehr with specific questions about Pearl (John Cecil Masterman's book The Double-Cross System and Prange's Verdict both reproduce it), but the FBI seems to have evaluated the effort as of negligible importance. There has been no report that its existence, or even Popov's availability as a double agent, was passed on to US military intelligence or to civilian policy officials. J. Edgar Hoover dismissed Popov's importance, noting (without basis) his British codename, Tricycle, was connected with his sexual tastes. In any case, he was not allowed to continue on to Hawaii and to develop more intelligence for the UK and US. Regardless, Prange demonstrates Popov's claim to have provided warning is overblown, and makes a case the notorious questionnaire was a product of Abwehr thoroughness.

More to the point, the Japanese did not need Abwehr assistance, having an active consulate in Hawaii which included on its staff an undercover IJN intelligence officer, Takeo Yoshikawa. The consulate had been making reports to IJN Intelligence for years, and Yoshikawa increased the rate of reports after his arrival in Japan. (Sometimes called a "master spy", he was in fact quite young, and his reports not infrequently contained errors.) Pearl Harbor base security was so lax Yoshikawa, and indeed anyone else, had no difficulty obtaining access, even taking the Navy's own harbor tourboat. (Even had he not, hills overlooking the Harbor were perfect for observation or photography, and were not off-limits.) Gossip with taxi drivers is supposed to have been one of his sources. Some of his information, and presumably other material from the Consulate, was hand-delivered to JIN intelligence officers aboard Japanese commercial vessels calling at Hawaii prior to the War; at least one is known to have been deliberately routed to Hawaii for this purpose during the summer. Most, however, seem to have been transmitted to Tokyo, almost certainly via cable. Many of those messages were intercepted and decrypted by the US; most were evaluated as the sort of intelligence gathering all nations routinely do about potential opponents and not as evidence of an attack plan. None of those currently known, including those decrypted after the Attack when there was time to return to those remaining undecrypted, explicitly stated anything about an attack on Pearl; the only exception was a message sent from the Hawaiian Consulate on 6 December, which was not decrypted until after the 7th and was thus moot with regard to any question of US foreknowledge. No cable traffic (the usual communication method to/from Tokyo) was intercepted in Hawaii until after David Sarnoff of RCA agreed to assist during a visit to Hawaii immediately before the 7th; such interception was illegal under US law, though it had been going on in New York for some time. Farago's POSTSCRIPT (Bantam paperback edition) offers the viewpoint of RCA personnel. In the final analysis, illegal co-operation of American cable companies likely changed little or nothing, since intercept stations were picking up some of the traffic anyway, and American intelligence failed to make optimum use of their information in any case.

[edit] Grid planning

Japanese Intelligence had, during the days prior to the attack, asked Yoshikawa to divide the waters of Pearl Harbor into a grid, to save time (and telegraph bills). He could say "six DDs section AA" instead of "six destroyers in the area northwest of Ford Island". Some people have referred to this as the "bomb plot" message. Note while Washington knew beginning the fall of 1941 of the "Kita Messages" or bomb plots, neither Admiral Kimmel or General Short were told. However, in the actual attack, the Japanese Navy did not use Yoshikawa's "bomb plot", as the exact locations of the ships in Pearl had never been forwarded to them. However, in Stinnett's book on page 106, is a figure "A. Sketch Used Reporting Enemy Anchoring Formation" obtained from a downed Japanese aircraft on December 7, 1941, so it seems SUZUKI's trip to Hitokappu Wan.^[7] (as given in SRN 116643 in the National Archives, SRNs - Special Research Navy - Japanese Naval messages said to have been translated in 1945/1946), prior to the attack, yielded the precise berthing locations. (A harbor chart reproduced in I-boat Captain, presumably based on Yoshikawa, erroneously lists some of them.)

While the Japanese, in addition to Hawaii, had the Panama Canal Zone and the Philippines under surveillance, Pearl Harbor was the only installation now known to have been divided into a grid. However, examination of an aerial photo of Pearl Harbor at the time of the attack makes it plain a pilot could easily determine the locations of individual ships and their classes without reference to a guide. This Naval Historical Center photo of Pearl Harbor from the air is a clear example. It also handily debunks the claim Japanese residents of Hawaii chopped hundred-foot-long arrows in nearby sugar cane fields to point the way to Pearl. Even in the absence of any evidence of this claim (none has come to light), it is immediately apparent a hundred-foot arrow would appear negligibly small compared to the much larger capital ships clearly visible in the harbor.

[edit] Allied intelligence

Locally, Naval Intelligence in Hawaii had been tapping telephones at the Japanese Consulate before the 7th, and, among much routine traffic, overheard a most peculiar discussion of flowers in a call to Tokyo (the significance of which is still publicly opaque and which was discounted in Hawaii at the time), but the Navy's tap was discovered and was disconnected in the first week of December. The local FBI field office was informed of neither the tap nor its removal; the local FBI Agent in Charge later claimed he would have had installed one of his own, had he known the Navy's had been disconnected.

Throughout 1941, the US, Britain, and the Netherlands collected a considerable range of evidence suggesting Japan was planning some additional military adventure. The Japanese attack on the US in December was essentially a side operation to the main Japanese thrust to the South against Malaya and the Philippines—many more resources, especially Imperial Army resources, were devoted to these attacks as compared to Pearl Harbor. Many in the Japanese military (both Army and Navy) had disagreed with Adm. Isoroku Yamamoto's idea of attacking the US Fleet at Pearl Harbor when it was first proposed in early 1941, and remained reluctant through the Imperial Conferences in September and November which first approved it as policy (allocation of resources, preparation for execution), and then authorized the attack. The Japanese focus on South-East Asia was quite accurately reflected in US intelligence assessments; there were warnings of attacks against Thailand (the Kra Peninsula), Malaya, French Indochina, the Dutch East Indies (Davao-Weigo Line), the Philippines, even Russia. Pearl Harbor was not mentioned.

There are reports of concern at the War Department and in the White House about Japanese plans for the SE Asian region. There had even been a specific claim of a plan for an attack on Pearl Harbor from the Peruvian Ambassador to Japan in early 1941. (The source for this bit of intelligence has been traced to the Ambassador's Chinese cook. It was treated with skepticism, and properly so, given the state of planning for the attack.) Since Yamamoto had not yet then decided to even argue for an attack on Pearl Harbor, discounting US Ambassador Grew's report to Washington in early 1941, was quite sensible. Later reports from a Korean labor organization also seem to have been regarded as unlikely, though they may have had better grounding in actual IJN events. There has been uncovered no record of a serious belief or conviction by anyone in US or UK military intelligence, or among US civilian policy officials, prior to the attack, that Pearl Harbor or the US West Coast would be attacked.

The so-called "Winds Code" announcing the direction of new hostilities via a broadcast weather 'forecast', remains a curious and confused episode, demonstrating the uncertainty of meaning inherent in most intelligence information, and its handling/mis-handling - and in this case, even uncertainty about the existence of some intelligence information, or of its active removal from official records, especially some years after the event. At most, however, the Winds system was to be implemented only if the communications between Japan and Washington were cut, and since this never obtained, there was no need for it. Note, however, in Safford's testimony on this topic he states very clearly London (not Washington) was the addressee of this message. Given this, any talk of intercepted "Winds" messages would appear to be specious.

However, there are two specific issues with this evaluation. First, there is Admiral King's indorsement of the Navy Court of Inquiry, page 344, reading in part, " ... (3) Admiral Kimmel was not informed of the implementation of the "Winds Message". Admiral Stark says he never got this information himself, but it is clear that it did reach Admiral Stark's office. This, together with the handling of other matters of information, indicates lack of efficiency in Admiral Stark's organization. ..." And, secondly, there exists more documentation for the "Winds Execute" - Briggs' Special Research History - SRH-051 (still a very heavily censored document in the US National Archives) - which relates an account of interception of the "Winds Execute", passing the message to ONI, and later, his direct order from Captain Harper^[8] not to testify in support of Safford at the Pearl Harbor hearings.

[edit] Advance warning and code breaking

Despite all these fumbles and confusions, in late November 1941, both the US Navy and Army sent war warnings to all Pacific commands. Although these clearly stated the high probability of imminent war with Japan, and instructed recipients to be accordingly on alert for war, they did not mention the likelihood of an attack on Pearl Harbor itself, instead focusing on the Far East. Washington forwarded none of the raw intelligence it had, and little of its intelligence estimates (after analysis), to Hawaiian commanders, Admiral Husband E. Kimmel and General Walter C. Short. Washington did not solicit their views about likelihood of war or Hawaiian special concerns. Washington's war warning messages have also been criticised by some (e.g., the US Army Pearl Harbor Board - "Do/Don't Messages") as containing "conflicting and imprecise" language.

Since the Army was officially responsible for the security of the Hawaiian facilities, and so of the Navy's ships in port, Army actions are of particular interest. Short reported to Washington he had increased his alert level (but his earlier change in meaning for those levels was not understood in Washington and led to misunderstanding there about what he was really doing). In addition, Short's main concern seems to have been sabotage from fifth columnists, which probably accounts for his orders Army Air Corps planes be parked close together near the center of the airfields. There seems to have been no increased urgency in the Army about getting its radar equipment properly integrated with the local command and control in the year it had been available and operational in Hawaii before the Attack. Leisurely training continued and the new early warning center was left minimally staffed. Anti-aircraft guns remained in a state of low readiness with ammunition in secured lockers. Long range patrol aircraft were not used effectively, remaining on a peacetime maintenance and use schedule. In Short's defense, it should be noted he (like Kimmel) had training responsibilites to meet, and the best patrol aircraft, B-17s and B-24s, were in demand in the Philippines and Britain, both of which had higher priority.

The mistakes made by both Hawaii and Washington meant little was done to prepare for an air attack. Inter-service rivalries between Kimmel and Short did not improve the situation. Particularly, most intelligence information was sent to Kimmel, assuming he would relay it to Short, and vice versa. Hawaii did not have a PURPLE machine (although, by order of Admiral Turner, four had been delivered to the British by October 1941), so it was dependent on Washington from intelligence from that (somewhat limited) source. However, since Short had no liaison with Kimmel's intelligence staff, he was usually left out of the loop. Henry Clausen reported the war warnings could not be more precise because Washington could not risk Japan guessing the U.S. was reading important parts of their traffic (i.e., most importantly PURPLE, despite the fact there was no known tactical or strategic info in that traffic). Additionally, Clausen claims military men of Kimmel and Short's seniority and background should have understood the significance of the warnings, and should have been more vigilant than they were, as for instance in scouting plane flights from Hawaii, which were partial at best in the period just before the attack. All other Pacific commands took appropriate measures for their situations. Like most commentators, Clausen ignores what the "war warnings" (and their context) explicitly warn, though indistinctly, against. Washington, with more complete intelligence than any field command, expected an attack anywhere on this list (Pearl Harbor not included). He, like most, also ignores what Kimmel, Short, and Admiral Claude C. Bloch (Commander, Fourteenth Naval District, responsible for Hawaii) did do. They took precautions against sabotage, widely expected as a precursor to war, and reported their preparations, although in Short's case, the most important of the three, Washington thought he had ordered something other than he was actually doing. They did not anticipate an air attack, despite good reason to have done so; no one did so explicitly.

One major point often omitted from the debate (though Costello covers it thoroughly) is MacArthur, unlike Kimmel, had complete access to decrypted PURPLE traffic (indeed, Stinnet quotes Whitlock to that effect), and was caught unprepared and with planes on the ground nevertheless, nine hours after the Pearl Harbor attack. Caidin and Blair also raise the issue.

One of the main considerations making an attack against Pearl Harbor unimaginable was the depth of Pearl Harbor — generally less than 40 feet. Depths of less than 150 feet had been (in the USN and others) widely believed insufficient for torpedo attack; at the time, torpedoes dropped from planes dove deeply before attaining running depth and in water that was not deep enough (like Pearl Harbor) would contact the bottom, detonating or embedding themselves in harbor mud. The British had proved torpedoes, modified for shallow water, could be effective in their attack on the Regia Marina at Taranto on November 11, 1940 (Battle of Taranto). The US Navy discussed this new development as can be seen in a July 1941 memo, but as Taranto was about 75 feet deep and Pearl less than 40, it was not considered the British attack method was relevant to a torpedo attack at Pearl. The Royal Navy had used Swordfish torpedo planes, and their slow speed was part of the reason the Taranto attack succeeded. The Imperial Japanese Navy no longer had any similar planes, so other methods were required. The Japanese independently developed shallow water torpedo modifications ("Thunder Fish") during the planning and training for the attack in 1941. Wooden fins were added to the tail and anti-roll "flippers" kept the torpedo upright once in the water. The fins kept the torpedo's nose level in the air and broke off when they hit the water. The level flight of the torpedoes helped keep them from diving too deeply into the mud (but, despite these modifications, several Japanese torpedoes did indeed dive to the bottom and several remain unaccounted for). This very simple modification of the Japanese torpedoes was not anticipated by the USN, and Admiral Bloch never pushed to install torpedo nets at Pearl. Nor, it seems, did anyone else. Due to the shallow anchorage (which continues to require regular dredgeing), the installation of torpedo nets would have severely restricted the mobility of vessels entering, leaving, and maneuvering in the harbor.

[edit] American carriers

Another piece of supposed circumstantial evidence is that US aircraft carriers were out of port at the time of the attack. This has been alleged by some as evidence of advance knowledge of the attack: the carriers were supposedly away so as to save them (the most valuable ships) from attack. In fact, the two carriers then operating from Pearl Harbor, Enterprise and Lexington, were on missions to deliver fighters to Wake and Midway Islands. (The third, Saratoga, was in routine refit in Puget Sound.) These assignments sent the carriers west, toward Japan and the Japanese Navy, lightly escorted. At the time of the attack, Enterprise was about 200 miles (370km?) west of Pearl Harbor, heading back. In fact, Enterprise was scheduled to be back on December 6th, but was delayed by weather. A rescheduling had her estimated time of arrival as 7:00, almost an hour before the attack, but she was also unable to make this schedule. Furthermore, at the time, aircraft carriers were classified as scouting elements for fleets, not capital ships; the most important vessels in naval planning even as late as Pearl Harbor were battleships (per the Mahanian doctrine of both the U.S. and Japanese navies at the time). As the only large warships available in the Pacific fleet, carriers became the Navy's most important ships during the gap between Pearl Harbor and the return of several battleships to duty in early 1943.

[edit] American immediate reaction

Closer to the moment of the attack, the attacking planes were detected and tracked as they approached by an Army radar installation being operated that morning as a training exercise. The Opana Point radar station, operated by two enlisted men (Pvts. Lockard and Elliot) plotted the approaching force, and their relief team plotted them returning to the carriers. These radar returns were thought, by the ill-trained junior officer (Lt. Kermit A. Tyler) in charge at the barely operational information center at Pearl Harbor, to be a flight of American bombers expected from the mainland. In fact those bombers did arrive, in the middle of the attack. Additionally, Japanese submarines were sighted and attacked outside the Pearl Harbor entrance a few hours before the planes arrived and at least one was sunk—all before the planes came within even radar range. It has been argued that this failure to follow up saved USS Enterprise. If she had been correctly directed to the source of the planes, she might have run into the six carrier Japanese strike force. Detection of one of the subs by the USS Ward might have provided enough notice to disperse aircraft and fly off reconnaissance, except, yet again, reactions of the duty officers were tardy.

[edit] War with Germany

Conspiracy theorists repeatedly point to the fact Roosevelt wanted the United States to intervene in the war against Germany. A basic understanding of the political situation of 1941 precludes this as good evidence Roosevelt knew of and allowed the Pearl Harbor attack. No attack by Japan was a guarantee the US would declare war on Germany. American public anger would be directed at Japan, not Germany, in the case of a Japanese attack. The Tripartite Pact alliance between Germany and Japan called for one to aid the other in case of attack, and so Japan could not reasonably claim America had attacked Japan in the event of a Japanese attack on the US. In addition, Germany had been at war with the U.K. since 1939, and with the U.S.S.R. since June of 1941 without Japanese assistance. There was a serious if low-level naval war going on in the Atlantic between Germany and the US Navy in the summer of 1941, in any case. Nevertheless, it was only Hitler's declaration of war, unforced by treaty, several days after the Pearl Harbor attack that brought the US into the European war.

Henry Clausen and Bruce Lee's "Pearl Harbor: Final Judgement" contains some interesting information on what intelligence Roosevelt and Winston Churchill possessed prior to the attack. On page 367 in the Appendix is a Purple message, dated 29 November 1941, from the Japanese Ambassador in Berlin to the Japanese Foreign Minister in Tokyo. A closing paragraph reads, " ... He (Ribbentop) also said that if Japan were to go to war with America, Germany would, of course, join in immediately, and Hitler's intention was that there should be absolutely no question of Germany making a separate peace with England. ..." Churchill (having full access to Purple, while Hawaii commanders - Short and Kimmel - did not) was well aware of this message, noting it in red ink^[9]

[edit] Controversy

Each of these points, amongst many others, remains controversial.

Conflicting stories regarding FOIA (Freedom of Information Act) requests for the source materials used, e.g., Sheet Number 94644, or materials available at the National Archives are also common among the debate. However much information has been said to have been automatically destroyed under a destruction of classified information policy during the war itself. Note various authors have nevertheless continued to bring classified Pearl Harbor materials to light via FOIA.

For instance, Sheet No. 94644 derives from its reference in the FOIA-released Japanese Navy Movement Reports of Station HYPO in November 1941. Entries for 28 November 1941 have several more items of interest, each being a "code movement" with specific message details given by associated Sheet Numbers. Examples are: Sheet No. 94069 has information on "KASUGA MARU" - this being hand-written (Kasuga Maru became CVE Taiyo); Sheet No. 94630 is associated for the IJN oiler Shiriya; and finally for Sheet No. 94644 there is another hand-written remark "FAF using Akagi xtmr" (First Air Fleet using Akagi's transmitter). It is known the "code movement" reports were largely readable at the time.^[10]

The three documents mentioned above (Sheet Numbers 94069, 94630, and 94644) are examples of materials which yet, even after decades and numerous specific FOIA requests, have not been declassified fully and made available to the public. Sheet Number 94644, for example, noted as coming from Akagi's transmitter and as a "code movevment" report, would have likely had a reported position.

Another issue in the debate is the fact neither Admiral Kimmel or General Short ever faced court martial. It is alleged this was to avoid disclosing information conspirators would not want to see made public. When asked, Kimmel replied, "Will historians know more later? Kimmel's reply to this was: ' ... I'll tell you what I believe. I think that most of the incriminating records have been destroyed. ... I doubt if the truth will ever emerge.' ..."^[11]

[edit] Some remaining classified materials relating to Pearl Harbor

A. All trans-oceanic telephone conversations (transcripts and recordings) between President Roosevelt and Churchill during November (of interest is especially November 26th) and December 1941 (the first week in particular). Much of this is based on fictional documents with an often claimed location of "Roll T-175" at the National Archives. There is no Roll T-175; NARA does not use that terminology. Also see [2]

B. Full and "true copy" RDF (Radio Direction Finder) records from all of the US Navy's Pacific facilties as well as those of Allies, for November 1941 and December 1941.

C. Complete and "true copy" of all raw intercepts of IJN Operations traffic for 1941, including all communications information (eg, Frequencies Used, Call Signs, TOI, Originator, Action/Information, ..., etc.). SRN-115376 and SRN-116643 are of particular interest for some.

[edit] Notes

1. ^ Conclusions, "Signals Intelligence and Pearl Harbor: The State of the Question" from Intelligence and National Security, Prof. Villa and Dr. Wilford, Volume 21, Number 4, August 2006, pages 549-551.
2. ^ Rhapsody in Purple: A New History of Pearl Harbor" in Cryptologia, July (pages 193-229) and October (pages 346-467) issues of 1982.
3. ^ [C.H. Baker, "Nanyo" 1987.
4. ^ For example, page 317, " ... same ham-fisted operator ..." for CV AKAGI; and Chapter 21, "Self-Deception" Note No. 19 " ... Did the Japanese Paint Us a 'Picture.' ...", page 547.
5. ^ Prange, At Dawn We Slept, page 416
6. ^ Parker's "The Unsolved Messages of Pearl Harbor", Cryptologia, 1991, Volume 15, Number 4, pgs. 295-313 has, " ... One of the most significant of the intercepted messages was sent 1 December 1941. It offered a tantalizing clue as to the whereabouts of the objectives. One of the tankers assigned to the Strike Force was Shiriya ..."
7. ^ Called Tappan Bay in Layton.
8. ^ SRH-051, page. 16
9. ^ David Irving, Churchill's War, Volume Two, page 220.
10. ^ Pelletier, Cryptolog, Summer 1992, page 5.
11. ^ Brownlow, op. cit., pages 178-179.

[edit] Further reading

[edit] External links

• Did Roosevelt know in advance about the attack on Pearl Harbor yet say nothing? — The Straight Dope, Straight Dope Science Advisory Board, February 28, 2001
• The Independent Institute: Pearl Harbor Archive — Mostly a Stinnett site, but also has Pearl Harbor articles, debates, interviews, transcripts, book reviews, books, and Pearl Harbor documents
• The National Defense Authorization Act (where it is noted that available intelligence regarding an impending attack was not conveyed to the American commanders at Pearl Harbor;page 121, section 546).
• Too Late for Pearl Harbor — An article detailing the amount of Japanese code that was readable to allies before the attack, refuting key points in Stinnett's "Day of Deceit."
• Communism at Pearl Harbor — An article proposing that the Russians maneuvered the US into war
• An Interview with Robert Stinnett and WWII Vet O'Kelly McCluskey.
• Foreknowledge of Pearl Harbor? No!: The story of the U. S. Navy's efforts on JN-25B — Excellent in depth article illustrating the problems with Stinnett and Wilford's claims regarding JN-25.
• The Myths of Pearl Harbor — Extensive site debunking claims of advance knowledge of the attack.
• Pearl Harbor - Mother of All Conspiracies Pro conspiracy site.
• The Great Pacific War — 16 years before Pearl Harbor attack, an English naval writer Hector Bywater uncannily prophesied in detail the war in the Pacific.
• Pearl Harbor In the Wake of the Prophet — It prophesied the Pacific War in detail, not only its operational modes, but its inevitable result.
• Pearl Harbor: The Controversy Continues Top-notch article on foreknowledge as well as steps to provoke Japan

Coordinates: 21°22′N 157°57′W