Arizona Memorial


Pearl Harbor

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Wilford, Timothy.

1. "Decoding Pearl Harbor: USN Cryptanalysis and the Challenge of JN-25B in 1941." The Northern Mariner 12, no. 1 (Jan. 2002): 17-37.

"[A]n examination of key letters and message-intercepts ... suggests that the USN could partially read Japanese naval traffic on the eve of the Pacific War.... The new evidence lends more support to revisionist interpretations than to traditionalist interpretations.... Future interpretations of USN cryptanalysis must assess how much [emphasis in original] was currently read through JN25B decryption." This article received the Keith Matthews Prize for the best article of 2002 from the Canadian Nautical Research Board.

2. Pearl Harbor Redefined: USN Radio Intelligence in 1941. Lanham, MD: University Press of America, 2001.

For Ford, Journal of Strategic Studies 26.4, "[t]he main strength of Wilford's book lies in its meticulous analysis of the relevant archival sources. The author is careful to avoid arriving at conclusions which cannot be supported by the evidence which he has consulted. Of equal importance, previous hypotheses regarding the intelligence failure at Pearl Harbor are paid due heed, with a careful evaluation of their strengths and weaknesses."

Kruh, Cryptologia 26.2, notes that "[f]rom the outset, Wilford declares his loyalty to the revisionists; his views echo their claims of censorship, missing documents, illogical statements, and overlook or belittle warnings issued between November 24 and 28." Wilford, Cryptologia 27.1/70-71, takes exception to Kruh's dismissal of his work. He states that his central thesis, which he believes is supported by archival and other research, is that "the USN gathered sufficient radio intelligence to predict the likelihood of a Pearl Harbor attack, although the Hawaiian commanders received insufficient forewarning." Kruh, Cryptologia 27.1/71-72, responds to Wilford's letter.

See also, Jacobsen, "Foreknowledge of Pearl Harbor? No!: The Story of the U.S. Navy's Efforts on JN-25B," Cryptologia 27.3 (Jul. 2003): 193-205.

3. "Watching the North Pacific: British and Commonwealth Intelligence before Pearl Harbor." Intelligence and National Security 17, no. 4 (Winter 2002): 131-164.

"Throughout 1941, British Intelligence pointed to a war with Japan in South-East Asia.... British Intelligence, according to some sources, also suspected that a Japanese attack on Pearl Harbor was imminent, an assessment shared with the United States."

Bath, NIPQ 19.3, notes Wilford's thesis that the Japanese fleet may have used low power, low-frequency ship-to-ship communications that allowed British DF stations to locate the ships advancing on Pearl Harbor. That information may have been passed to the U.S. authorities. The reviewer comments: "Much conjecture, little new, hard evidence."

Winton, John [pen name of John Pratt]. ULTRA in the Pacific: How Breaking Japanese Codes and Cyphers Affected Naval Operations Against Japan, 1941-45. London: Leo Cooper, 1993. Annapolis, MD: Naval Institute Press, 1993.

Kruh, Cryptolog 15.3, finds that this book combines a "well written, chronological format" with a "detailed examination of the practical applications of Ultra intelligence." The material on British FECB work against JN-25 "is basically a rehash" of Rusbridger and Nave. Overall, this is a "fine work that shouldn't be marred by a rash comment."

The MI 21.1 reviewer says that the reader comes "away with a real sense of the skill and devotion that code breakers brought to their work." This is a "balanced work that will appeal to the crypto fan and the historian" and is a "quickly read presentation." Best, I&NS 10.1, concludes that ULTRA in the Pacific "is an entertaining and well written piece of work.... [W]hat separates Winton's book from its peers is its accessibility. This is not a dry academic tome; it is a book that communicates its interest in the subject and shows very clearly both the benefits to be gained from a superior intelligence-gathering capacity and the limits to its utility."

According to Bates, NIPQ 10.3, Winton "does not subscribe to the conspiracy theory that Churchill knew about Pearl Harbor ... but did not tell Roosevelt." He "does, however, say that '...there had been plenty of intelligence in the months before Pearl Harbor which, with hindsight, can clearly be shown to have revealed Japanese intentions'.... Regarding the shootdown of Admiral Yamamoto, Winton states that Admiral Nimitz '... obtained approval from everyone from President Roosevelt downwards.'" The reviewer take issues with these conclusions: "I ... do not believe there was plenty of intelligence before Pearl Harbor to predict the attack.... I also do not believe the decision to shoot Yamamoto down went any higher than Nimitz.... I have some problems with this one, I suggest you approach it with skepticism. But, it's a readable, interesting book that provides some new information and clearly identifies the contribution of radio intelligence in the Pacific in WW II."

Barnhart, I&NS 11.2, says that the "most original parts of ULTRA in the Pacific deal with Great Britain's role ... and its intelligence contributions.... Unfortunately, as Winton admits, Britain left most of the intelligence work to the Americans.... Winton is curiously silent upon the role of the Commonwealth services.... [R]eaders concerned with the role of intelligence in the Pacific[] would do better to consult John Prados' latest work, Combined Fleet Decoded."

Wohlstetter, Roberta.

1. Cuba and Pearl Harbor: Hindsight and Foresight. Santa Monica, CA: Rand, 1965.

Clark comment: This work takes Wohlstetter's "signals" vs. "noise" analysis, developed initially in relation to the Pearl Harbor disaster, and applies it to the Cuban Missile Crisis. Constantinides notes that the study is based on open sources, a circumstance that may limit its usefulness. See also, Wohlstetter's article, "Cuba and Pearl Harbor: Hindsight and Foresight," Foreign Affairs 43 (Jul. 1965), 691-707.

2. Pearl Harbor: Warning and Decision. Stanford, CA: Stanford University Press, 1962. D76792W6

Clark comment: Wohlstetter is a superb beginning point for any discussion of the problems faced by intelligence analysts in their relations with policymakers, specifically the "signal to noise" problem.

Pforzheimer says that the continuing value of Wohlstetter's work "lies not only in the intelligence background of the Pearl Harbor attack, but also on vital questions of intelligence estimates, alerts, and indications and warning systems which the author presents in depth." Constantinides calls the book "an outstanding analysis," but also recognizes that some critics argue that Wohlstetter's model works only when deception is not involved. Kirkpatrick, Studies 7.3 (Summer 1963), calls Wohlstetter's a "magnificent analysis."

3. "Sunday, December 7, 1941, and the Monday Morning Quarterbacks." Air Force Magazine, Dec. 1966, 82-86.

To Sexton, this is an "authoritative review of the background of the Pearl Harbor disaster." Wohlstetter finds nothing in the evidence that would have given a pointed warning of the impending attack. She sees "conspiracy theorists and amateur evaluators of Comint ... finding cause and effect relationships where none exist."

Worth, Roland H., Jr. Secret Allies in the Pacific: Covert Intelligence and Code Breaking Cooperation between the United States, Great Britain and Other Nations Prior to the Attack on Pearl Harbor. Jefferson, NC, and London: McFarland, 2001.

Seamon, Proceedings 128.1 (Jan. 2002), says that "few studies ... have ranged so widely and probed so deeply into prewar intelligence gathering" as this book does. Along the way, the author "all but demolishes conspiracy theories claiming President Franklin Roosevelt was responsible for the attack."

Although he identifies some "shortcomings" in this work, Jacobsen, I&NS 17.3, concludes that the author "does provide a very readable general overview of the Sigint, and to a lesser degree, the covert intelligence activities of the Allies against Japan" leading up to the attack on Pearl Harbor. Kruh, Cryptologia 26.2, comments that "Worth brings together pieces of often isolated details." which allows the reader "to gain a sense of how the chain of [intelligence-sharing] alliances came to exist, how they functioned and what were their limitations." However, "knowledgeable readers will not find many surprises."

Yoshikawa, Takeo, and Norman Stanford. "Top Secret Assignment." U.S. Naval Institute Proceedings 86, no. 12 (Dec. 1960): 27-39.

Tells the story of a Japanese ensign's espionage assignment in Hawaii prior to the Pearl Harbor attack.

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