Fourteen Part Message, Dec. 6, 1941

At 7:20 a.m. Saturday, December 6, 1941, a Navy intercept station near Seattle intercepted a message from Tokyo to the Japanese Embassy in Washington, announcing that the situation had become very delicate and that Japan would shortly send a fourteen-part message in reply to Secretary of State Cordell Hull's memorandum of November 26.

Soon afterward, beginning at 8:05 Seattle time, the message began arriving, in Japan's diplomatic code, known to American cryptographers as "purple." The intercept station had received the first thirteen parts by 11:52 a.m. By midafternoon, the thirteen parts had been sent to Washington, where Navy cryptographers (OP-20G) began breaking the message.

The fourteenth and final part was intercepted at 2:38 a.m. Sunday, December 7, decrypted and delivered to the White House about 9:45. At 4:37 another intercept directed Nomura to deliver the message to Hull precisely at 1:00 p.m. Washington time, and an intercept at 5:07 directed the embassy to destroy all remaining codes, ciphers and secret documents in the Japanese embassy.

The embassy had already discharged all of its locally hired typists. While frantically trying to destroy classified material, inexperienced foreign service officers had to type the documents into proper diplomatic form.

They missed the delivery deadline.

Unsuspected by the Japanese, President Roosevelt and Cordell Hull had already read the Japanese response well before Nomura called on Hull to deliver it. Apparently the "time of delivery" and code destruction intercepts were not delivered to the president until after news of the attack had reached Washington, though General Marshall attempted to warn General Short and Admiral Kimmel in Pearl Harbor about the two messages. That communication didn't reach its destination until after the attack.