In the months before the Pearl Harbor attack, a comprehensive radio denial and deception plan fed the Americans information that seemed to confirm that the Imperial Japanese Navy was doing what it had exercised for decades—awaiting the attack of the U.S. Pacific Fleet. But Admiral Yamamoto had changed the script.
Hanyok, Robert J.
"“Catching the Fox Unaware”—Japanese Radio Denial and Deception and the Attack on Pearl Harbor,"
Naval War College Review: Vol. 61
, Article 10.
Available at: http://digital-commons.usnwc.edu/nwc-review/vol61/iss4/10