Fort Huachuca, AZ. – On the night of Dec. 6, 1941, a message to a Japanese delegation in Washington D.C. was intercepted, broken and distributed by the Signal Intelligence Service, or SIS.
This message, which would become known as the Fourteen Point Letter, clearly spelled out the Japanese claims that America was trespassing in the Far East. President Roosevelt, after reading the first 13 parts at 9:30 p.m., commented that this meant war. Officers in the SIS agreed, and felt sure that American Armed Forces would be on full alert.
The 14th part of the letter began to arrive at 5 a.m. on Dec. 7, 1941. It was deciphered by the Americans before the Japanese embassy. The letter declared in a single sentence that Japan was breaking off relations with the United States, and that the U.S. secretary of state should be notified at 1p.m. — dawn, in Hawaii. The president was informed immediately.
Gen. George Marshall, chief of staff of the Army, decided to alert the commanders of both the Hawaiian and Philippine department that the potential for attack was high. However, because of the sensitivity of the message, it was sent by telegraph. It wasn’t delivered to the ground commander in Hawaii until the Japanese bombers were flying through the morning fog over Pearl Harbor.
Source: http://www.army.mil
Station HYPO 
6 December 2020 at 12:16
The 2 posts today were incredible. Thank you Mario.
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6 December 2020 at 17:44
What was ironic was that they sent the alert message by Western Union, knowing that the Navy was in communication with Pearl Harbor, but the Army was not. The picture of the WU delivery person trying to get on base in “Tora, Tora, Tora” is almost tragic.
Of course, had the message been delivered Saturday afternoon on the 6th, and the Fleet sortied, all those Battleships might have been sunk in deep water with an even greater loss of life, and the initial attack would have then been directed at the port facilities and the fuel tanks.
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6 December 2020 at 19:43
Thank you very much, Mario, for both of today’s posts!
I’m one who believes that President Roosevelt’s message to the Emperor was written for the sake of the historical record. The timing for its transmission pretty much makes this conclusion of myself and quite a few others (John Toland being just one) obvious.
What too many writers have failed to realize, and I’ll be quick without going into too many details: Over the course of the eight government investigations conducted into Pearl Harbor between December 1941 and June 1946, three different individuals were claimed to have seen the first 13-parts of the final 14-part Magic diplomatic intercept. All three of these individuals are said to have replied upon reading those first 13-parts, “`This means war!’ (or words to that effect)” in one of the three instances.
There were and are many other indications of a Japanese-American war in the Magic that was declassified and published during the course of the Joint Congressional Committee’s investigation into Pearl Harbor. These “magic” (Japanese diplomatic and consular) messages that indicate war was soon going to happen are published in exhibits one and two of the Joint Congressional Committee (JCC) in Part 12 of the 39-volume Pearl Harbor Attack Hearings.
Our own government also took a number of steps in the last few days of peace that are an excellent indication our people—in Washington, D.C. and in Hawaii—realized that war was about to commence. (1) U.S. Navy changed its major cryptographic system about the same time the IJN changed its major (JN-25) system, e.g., 1 December 1941. (2) We ordered the destruction of codes and secret papers on Wake Island and on Guam on 4 December 1941 (U.S. date). You folks who are in communications intelligence as professionals should appreciate this “little” point: We did not order U.S. facilities on Johnston Island, Canton Island, Samoa or Midway to destroy their codes and secret documents.
I’m writing this from a hotel room on Oahu and don’t have a desktop computer to write this on. I also don’t have my research files with me. That said, to quote Rear Admiral Royal E. Ingersoll, the then “assistant Chief of Naval Operations” (as his position was known in 1941: “The destruction of codes meant war in 2 or 3 days.” (Again, we ourselves were doing this as specific IJN objectives, on 4 Dec. 1941, U.S. date.)
I thought of writing a brief essay on U.S. code destruction to send to you to consider posting this year, but, unfortunately, I ran out of time.
My wife and I will have our first MS on the subject of U.S. entry into WWII ready for publication by early November of next year for the 80th anniversary. Our first book will be titled, “Time to Reexamine Pearl Harbor.”
There is absolutely no doubt in my mind that high level Americans—including President Roosevelt—knew Japan was going to make war against the United States on Sunday, 7 December 1941. I began serious work on Pearl Harbor history in October 1983, although my interest in the subject started in the mid-1950s when my family was first stationed at Submarine Base, Pearl Harbor. To repeat what I’ve written in the past, I’ve read all 39-volumes of the Pearl Harbor Attack Hearings. What I’m doing with Pearl Harbor is THE most enjoyable work of my 72-years.
I am not a critic of U.S. entry and participation into WWII. To paraphrase Winston Churchill, the outcome of the Second World War was determined (written in blood, we might say) on Oahu on 7 December 1941.
As for next Saturday, 12 December 2020: GO NAVY! BEAT ARMY!
Andy McKane, Marriott’s Ko Olina Beach Resort, Oahu, Hawaii.
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6 December 2020 at 20:35
A back story of the fourteenth part memorandum and its delay to Washington is found in recent Japanese research on this subject. On the evening of December 6, 1941 (9:00 PM EST) President Roosevelt sent a telegram to Emperor Hirohito in order to salvage diplomatic talks that was soured by the Hull note. The fourteenth part memorandum was being prepared for transmission to the Washingtom embassy when news of the Roosevelt telegram was received in Tokyo, the IJA seized it and withheld it from the emperor for security reasons until after the attack on Kota Bharu. The fourteenth part memorandum, that was drafted on December 5, was revised to reflect the contents of the Roosevelt telegram of December 6 and became the emperor’s “reply” to the U.S. The rest is history.
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