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Pearl Harbor: The Successes and Failures of U.S. and Japanese Intelligence

U.S. History of Intel

Nicholas Bonacquisti

on 20 April 2013

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Transcript of Pearl Harbor: The Successes and Failures of U.S. and Japanese Intelligence

Pearl Harbor: The Sucesses and Failures of
Japenese and U.S. Intelligence Nicholas Bonacquisti
Kyle McIntyre
John Mehm
Matt Sutton Agenda Background video
Japan-Success/ Failure
U.S.- Success/ Failure Role of the Japanese Imperial Army and Navy
Collection Methods
Isoroku Yamamoto
Special Intelligence
Translating Codes Japanese Intelligence Agencies During WWII
Signals Intelligence 393
Attaché 102
Prisoner-of-war questioning 27
Captured Documents 2
Spies 7
Army intelligence 11
Ministry of Foreign Affairs information 2
Open Source Intelligence (radio, etc.) 110
Open Source Intelligence (published material, etc.) 769
Other 23
Source unclear 38
Total 1484 Information source Number of items of intelligence and data gathered HUMINT
Yakeo Yoshikawa The Role of Spies for the Japanese The Reason to Attack The Japanese government believed that the only way to solve its economic problems was to expand into its neighbor’s territory and take over its import market; to this end, Japan had declared war on China in 1937. This resulted with trade embargos and sancations placed against the Japanese government in order to cripple the economy, by the US. This proved to provoke the Japanese, who were more determined to stand their ground. Japanese Objective The Japanese plan was simple: Destroy the Pacific Fleet. That way, the Americans would not be able to fight back as Japan’s armed forces spread across the South Pacific Traffic Analysis The only reliable intelligence analysis that the military had Major Assumption Proved False HUMINT was not prevelent prior to Pearl Harbor Cryptanalysis Extremely Underfunded
MAGIC and PURPLE contained diplomatic messages
Navy and Army comminication was poor Communications Up to 3 Weeks
Army and Navy lacked communication Japanese Intelligence Failures 14 Part Message Decoded on the 6th
Warning not percieved as urgent
Warning finally sent via Western Union December 6th and 7th Commander Minoru Genda changed
plans for the attack on carriers Poor Commanding Japanese initial main
target was battleships Commander Genda and his suprise or no suprise plan Did not account for weather on the morning of Advised carriers were not in port but proceeded with attack U.S. Intelligence Successes Intelligence derived from intercepting messages
transmitted by radio or similar means.
Subdivided into two areas:
Traffic analysis COMINT Col. William F. Friedman
August, 1940 Cryptanalysis Bomb plot message
September 24
Deadline messages
November Intercepted Messages "There are reasons beyond your ability to guess why we wanted to settle Japanese-Americans relations by the 25th, but if within the next three or four days you can finish your conversations with the Americans...in short if everything can be finished, we have decided to wait until that date. This time we mean it, that the deadline absolutely cannot be changed. After that things are automatically going to happen." November 22, 1941 Revealed three significant events:
November 1, 1941
Complete Japanese Naval Communications change
November 16, 1941
Lack of Japanese carrier and submarine communication
December 1, 1941
Complete Japanese Naval Communications change Traffic Analysis Japan formally breaks relations with the U.S.
1 O'clock message
Intercepted by MAGIC on December 7, 1941, 4:30 A.M. EST Cryptanalysis: 14-Part Message Successful on two accounts:
Possibility of Japanese attack on Pearl Harbor
Avoid mirror-imaging HUMINT Ambassador Joseph Grew "My Peruvian Colleague told a member of my staff that he had heard from many sources including a Japanese source that the Japanese military forces planned, in the event of trouble with the United States, to attempt a surprise mass attack on Pearl Harbor using all of their military facilities..." January 27, 1941 November 3, 1941 U.S. should avoid “any possible misconception of the capacity of Japan to rush headlong into a suicidal conflict with the United States.... Japanese sanity cannot be measured by our own standards of logic. Successes:
Daily messages including the deadline messages, 14-part message, and 1 O'clock message
Three naval events
Correctly forecasted attack on Pearl Harbor
Warned against mirror-imaging Summary Training Separated training before attack Training missions did not replicate Pearl Harbor Poor training conditions killed many pilots and destroyed aircraft Did not train in formations used on Pearl Harbor Because of the confusion only 31% of targets were hit U.S. Intelligence Failures Contact Information and Questions
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