There is so much evidence of official warnings to American Service commanders to be prepared for surprise attack that the expectation of such attack is established beyond question. For example, there is Admiral Stark's 'war warning' signal of November 27th to the American Navy that 'an aggressive move by Japan is expected within the next few days'. Moreover, the sighting of the Japanese convoys off Camo Point on December 6th (or nearly two days before the attack on Pearl Harbour) was known in Manila the same day, and presumably was also known in Washington. The American authorities must therefore have been aware that Japan was on the move and about to attack somewhere. What seems never to have crossed their minds was that the attack would come at Pearl Harbour. But a miscalculation of this kind was hardly the fault of the Japanese; especially as the American Ambassador in Japan had previously warned Washington that this very attack was being freely rumored in Tokyo.
TOKYO, January 27, 1941-6 p.m.
[Received January 27-6: 38 a.m.]
125. A member of the Embassy was told by my ------- colleague that from many quarters, including a Japanese one, he had heard that a surprise mass attack on Pearl Harbor was planned by the Japanese military forces, in case of "trouble" between Japan and the United States; that the attack would involve the use of all the Japanese military facilities. My colleague said that he was prompted to pass this on because it had come to him from many sources, although the plan seemed fantastic.