Chapter 12: 12. December 6, Part 1 Collecting “Intelligence” and Determining Policy

With the perspective of hindsight, it is easy to spot the significant clues that should have given warning that the Japanese might attack Pearl Harbor. Out of fairness to the participants in the drama that was unfolding in 1941, however, we should keep in mind the situation as it appeared to them. A mass of information was coming into Washington in many forms from all over the world. Bits and pieces of information came from various sources—from diplomatic contacts, from cable intercepts, including MAGIC, from our military and naval attachés, from direct observations, overflights, radio direction findings, and so on. Much of it was not in English. And much of this foreign-language material was in code as well. We were able to decode, translate, and read a great deal of that, although not all, quite promptly. The coded cable traffic alone was extremely heavy. Thus the amount of this material that was available toward the end of 1941 was almost overwhelming.

Many persons, each with his or her own expertise, played a role in the process of collecting the raw data that go to provide “intelligence.” There were code specialists, communications specialists, security specialists, decoders, translators, and couriers. There were code clerks who listened to foreign radio broadcasts and could decipher Morse code, linguists familiar with Japanese, and radio technicians who could determine the location of naval vessels and military units by intersecting radio beacons. There were others at our various stations all over the world who picked cable intercepts out of the air and transmitted them to Washington. Each was familiar with only a small part of the total picture. No single person had access to all this information. Few of the many specialists were sufficiently aware of the broad picture to be able to comprehend the significance of the data they accumulated. And no one had any reason to feel a sense of urgency because no one knew what was going to happen on December 7.

The responsibility for collecting, analyzing, disseminating, and employing information was divided among various offices and divisions of the military and the administration, each with its own specialized experts. Roughly speaking, data was collected by technical personnel in “communications.” Raw data was then integrated and analyzed by specialists in “intelligence” offices or divisions, persons who had the training, experience, background, and knowledge of policy sufficient to sift the wheat from the chaff, to recognize what was pertinent and what was not, to analyze and interpret it, and to decide what information should be disseminated and to whom. These “intelligence” specialists needed to understand not only military operations, the defensive and offensive capabilities of our forces and of our potential allies and enemies, but also the diplomatic situation and government policy.

Once the raw data collected was converted into “intelligence,” other specialists were responsible for disseminating it and issuing commands to the field commanders. This responsibility was usually in the hands of “War Plans” or “Operations” divisions. Final policy decisions were then made on the basis of the diplomatic and political situation by the government’s administrative officials, the president and his cabinet, after taking into consideration the advice of the Army’s chief of staff and the chief of naval operations.

The various specialists cooperated. But at the same time they were protective of the prerogatives of their own office or division, and anxious to prevent outsiders from invading their department’s turf. Thus the jurisdiction of each office or division was carefully prescribed. To avoid conflict, each was careful to follow channels. “Communications” collected data; “Intelligence” analyzed and interpreted it; orders to field officers, in line with the administration’s policy decisions, went out from “War Plans” or “Operations.” Although the system usually functioned smoothly, its operation was sometimes disturbed as changes were made in procedure and personnel.

In the Army, the Signal Intelligence Service (SIS) collected information and transmitted it to Army Intelligence (G-2). The War Plans Division (G-5) formulated plans under the direction of the Army chief of staff (ACS). The president, the commander-in-chief, was responsible for overall policy. But orders to the field were issued by the chief of staff, “the immediate advisor of the Secretary of War” and “the Commanding General of the Field Forces.”^[1]

In the Navy, the Office of Naval Communications collected data. Traditionally, the Office of Naval Intelligence (ONI) had had the responsibility for collating, analyzing, and disseminating this information to officers in the field. However, when Rear Admiral Theodore S. Wilkinson became director of ONI on October 15, 1941, he found that it had been reduced to a fact-gathering agency and the Navy’s War Plans Division had assumed the responsibility for analyzing the information that came in.^[2] The Navy’s top officer, the Chief of Naval Operations (CNO), was responsible for keeping the Navy’s commander-in-chief, the president, informed. And orders to the Navy’s field commanders were sent out by the CNO.

Step by step, as data journeyed through channels, from the technical specialists who collected it to the officers with training and experience who interpreted it, it became meaningful “intelligence.” “Intelligence” formed an extremely important component of the total 1941 picture. The Army’s chief of staff, General Marshall, and the Chief of Naval Operations, Admiral Stark, relied on the available “intelligence” when advising their field commanders on military strategy. The top administration officials, that is the secretaries of State, War, Navy, and the president himself, also strove to keep abreast of current “intelligence.” In 1941, this meant keeping up to date on the Japanese position through the diplomatic cables and other sources.

In the course of assembling, interpreting, and analyzing the data available, the most important “intelligence” was channeled to the men at the top. Even though each technical specialist involved in the complicated procedure was familiar with only a small segment of the total picture, the president and his top civilian and military advisers, who had the final responsibility for the “common defense” of the nation and for resolving diplomatic and political differences, had a bird’s-eye view of the overall situation. They were also provided with the country’s most perceptive military advice. By December 6, they were well aware, as a result of their access to MAGIC and other sources, that a clash with Japan was at hand. Their constitutional responsibility for national defense obligated them to protect this country and its citizens and to see to it that, insofar as possible, U.S. forces, wherever stationed, were properly provisioned, prepared, and alerted. Their constitutional responsibility did not call for inviting foreign intervention or defending other nations.

“Pilot Message” Alerts Washington to Expect Japan’s Reply to U.S. “Ultimatum”

Ever since November 26, when Washington officialdom had rejected the Japanese proposal for a modus vivendi, we had been anxiously awaiting Tokyo’s reply. We knew from reading cable intercepts that the Japanese considered our statement “humiliating” and that relations between our two countries were considered to be “de facto ruptured.” It was clear to us that U.S.-Japanese relations were at an impasse. But we had also read their government’s instructions to the two Japanese ambassadors to keep on talking and not “to give the impression that the negotiations are broken off.” So we knew their interest in continuing to meet with Secretary of State Hull was merely for the sake of appearances; it did not mean a change in their deadline.^[3]

On Friday, December 5, Rear Admiral Theodore S. Wilkinson, Director of the Office of Naval Intelligence, had set up “a 24-hour watch in the Far Eastern Section” and had established “a watch of the senior officers of the Department.”^[4] According to Navy Captain William A. Heard, then in charge of the foreign branch, Office of Naval Intelligence, “There was an elaborate arrangement for prompt notification to the Director of Naval Intelligence of any matter of interest to him.” Captain Heard had personally arranged for “a special week-end telephone line between the Office of Naval Intelligence and the State Department,” which “included my [Heard’s] telephone communication with both Military Intelligence and with the State Department.”^[5]

On Saturday, December 6, at 7:15 a.m., Washington, D.C., time, the Navy’s intercept station on Bainbridge Island (Washington state), across the Puget Sound from Seattle, started picking up a message in “Purple” addressed to the Japanese ambassadors in Washington.^[6] This coded message was relayed almost immediately, as was customary by TWX (teletype wire exchange) along with other messages that had been intercepted that morning, to Washington, D.C.^[7] It was received in Washington that same day, at 12:05 p.m.

Until a message had been decoded and translated, there was no way, of course, to know if it was important. Army and Navy had only just, on December 1, worked out an arrangement to share responsibility for handling the heavy traffic of Japanese intercepts, the Army had the responsibility for decoding and translating on even-numbered dates, the Navy on uneven-numbered dates. December 6 was an Army day. So when this message from Bainbridge came in, the Navy relayed it to the Army’s SIS^[8] and an Army cryptographic unit went to work right away. That was fortunate, for this message proved to be Tokyo’s announcement to her two Washington ambassadors that Japan’s formal reply to the U.S. note of November 26 was on its way. This message came to be known among those familiar with MAGIC as the “Pilot Message.”^[9] By 2:00 it had been decoded, translated, and typed up in finished form by the SIS men.^[10] Presumably the Japanese code clerks in their embassy were decoding and typing this same message at the same time as were our Army decoders.

This “Pilot Message” stated that the Japanese government had “deliberated deeply” with respect to the U.S. note and had drawn up a long 14-part memorandum that would be sent to the ambassadors separately. The reply would be transmitted in English, so it would only have to be decoded before it could be submitted to Hull. The situation was “extremely delicate,” Tokyo warned. When the ambassadors received the long memorandum, they should keep it secret for the time being. They would be wired special instructions separately “concerning the time of presenting this memorandum to the United States.”^[11]

About 2:00 Saturday afternoon, as soon as the “Pilot Message” was ready, SIS sent it to the Military Intelligence Division of the War Department’s general staff. From Military Intelligence it was distributed at about 3:00, either by Colonel Rufus S. Bratton, then chief of Military Division’s Far Eastern Section, or by one of his assistants, to the Army’s list of recipients—Hull, Stimson, Marshall, and Chief of War Plans Division Leonard T. Gerow (G-2).^[12]

The Navy courier, responsible for delivering Japanese intercepts to the White House and the others on the Navy’s list, was Lieutenant Commander A.D. Kramer. The White House was usually first on Kramer’s list and apparently Admiral Beardall, naval aide to the president at the White House, received the “Pilot Message” at about 4:00 in the afternoon, shortly before leaving his office for the evening.^[13] Admiral Wilkinson, Director of Naval Intelligence, was planning a party that Saturday evening for some of his fellow staff officers and he said he received the message in his office at about 6:00 p.m., just before he left for home.^[14]

After reading the “Pilot Message,” the top officers in the administration, Army, and Navy anxiously awaited the 14-part Japanese reply. Watching for the long Japanese memorandum was given top priority. Since FDR’s naval aide Beardall had plans for the evening, he arranged for a communication watch officer, Lieutenant Schulz, to stand by at the White House to deliver to the president any message that might come in during the evening.^[15]

The first part of Japan’s 14-part English-language message, heralded by the “Pilot Message,” began to come into Washington during the afternoon of December 6. And then the decoding began.

U.S. Overflights Sight Japanese Convoys in South China Sea Heading Toward Malaya

The steady stream of Japanese messages we were intercepting gave us substantial insight into the deliberations of the Japanese government. However, these intercepts were not our only source of information about their activities. Planes from Manila conducted reconnaissance flights on a regular basis over the South China Sea and reported on Japanese movements at sea. A December 6 cable from Admiral Hart, commander-in-chief of the Asiatic Fleet in the Philippines was received in the Navy Department in Washington at about 8:00 a.m. that same morning. It reported that two Japanese convoys consisting of 35 ships escorted by eight cruisers and 20 destroyers had been sighted south of Indochina heading toward Malaya.^[16] These convoys were dangerously close to the line drawn by the ADB powers (American/Dutch/British) and designated in their secret April 1941 Singapore meeting as the limit beyond which the Japanese could not advance without inviting “active military counter-action.”^[17] Both convoys were south of the southern tip of French Indochina, so they had already crossed latitude 10° North. Since they were heading west toward the Isthmus of Kra, and had arrived at longitudes 106.20° East and 105° East, they were expected soon to pass the critical north-south line, 100° East. Hart’s message also reported “30 ships and one large cruiser” sighted by his scouting force anchored in Camranh Bay off the southeast coast of Indochina, a couple of hundred miles north of Saigon (since renamed Ho Chi Minh City).

Shortly after Hart’s cable reached the Navy Department, the State Department received a message from U.S. Ambassador John G. Winant in London confirming that these convoys were converging on waters the ADB powers considered inviolable.^[18] It was not clear, however, just where they were headed. The British undersecretary of foreign affairs, Sir Alexander Cadogan, was “uncertain as to whether destination of parties is Kra [Malaya] or Bangkok [Thailand].”^[19] But there could be no doubt that Japanese ships and troops were moving into position for some operation in the vicinity of the Malaysian Peninsula and/or the Dutch East Indies. The Dutch were much alarmed at the proximity of such large concentrations of Japanese troops.

On December 5, U.S. Military Attaché Merle-Smith in Australia had sent information about these convoys to General MacArthur in the Philippines and to General Short in Hawaii. The fact that Japanese troops were on the move in the southwest Pacific was taken as confirmation in Hawaii of the word they had received from Washington: that the immediate threat of a Japanese strike was to southeast Asia.^[20]

Intercepted Messages from Italy, Japanese Embassy (Washington), Tokyo, Indicate War is Imminent

In Europe the three Axis Powers—Germany, Italy, and Japan—were following the diplomatic events unfolding in Washington. We learned on December 6, that Premier Benito Mussolini had told the Japanese ambassador to Italy that he had “been carefully watching the progress of the Japanese-U.S. talks.” Mussolini charged the United States with “utter bull-headedness” and FDR with being of a “meddlesome nature.” Mussolini told the ambassador that he was in complete sympathy with Japan’s desire to create “a New Order in East Asia.” The ambassador then asked, “[S]hould Japan declare war on the United States and Great Britain . . . would Italy do likewise immediately?” Mussolini replied: “Of course.”^[21]

A December 5 message addressed to the Japanese ambassadors in Washington from Tokyo, also decoded and translated in Washington on December 6, provided one more clue to Japan’s intentions. This cable was short: “Will you please have Terasaki, Takagi, Ando, Yamamoto and others leave by plane within the next couple of days.”^[22] When delivered to the Navy recipients of MAGIC, a penciled footnote identified Terasaki, second secretary in the Japanese embassy, as “head of Japanese espionage in Western Hemisphere. He and his assistants,” the note read, “are being sent to South America.”^[23]

Also on December 6, we translated two other “Purple” messages dealing with the destruction of codes at the Japanese embassy in Washington. One message from the embassy in Washington advised Tokyo that the codes had been destroyed but requested permission, “since the U.S.-Japanese negotiations are still continuing[,]” to delay “the destruction of the one code machine.”^[24] The wire from Tokyo explained that the embassy was “to burn one set” of code machines but “for the time being to continue the use of the other.”^[25]

That same afternoon we intercepted and decrypted another short Japanese message from Tokyo reminding the embassy in Washington of the importance of “preserving secrecy” with respect to the “aide memoire,” the 14-part reply to our note of November 26. “[B]e absolutely sure not to use a typist or any other person” in its preparation.^[26]

Still another significant Japanese intercept from Honolulu to Tokyo was read that day. This message, transmitted in a code not yet decrypted, had been picked up in San Francisco on November 18 and airmailed to the SIS in Washington on or about November 21. It could be decoded and translated only after the cipher was solved on or about December 3, but it was available to our people in Washington on December 6.^[27] This intercept reported movements of U.S. naval ships in and out of Pearl Harbor. No hint of its contents, or of its existence, was relayed to the commanders there.

Japanese Offices Worldwide Acknowledge Code-Destruct Order

Japanese diplomatic offices all around the world seemed to be preparing for an emergency. On December 3 we had translated a Tokyo message to the Japanese embassy in Washington ordering them to destroy all but one code machine and to burn all codes but the one used with the surviving machine. When this had been done the embassy was to cable one word to Tokyo: “haruna.”^[28] On delivering this intercept to FDR, his naval aide Beardall called it to FDR’s attention. The president read it and asked, “Well, when do you think it will happen?” In other words, when did he expect war to break out? Beardall replied, “Most any time.”^[29]

On receipt of this intercept, a young officer, at Colonel Bratton’s request, went by the Japanese embassy in Washington during the night. He saw officials of the Japanese embassy actually burning their code book and ciphers. On December 6, the Office of Naval Intelligence learned about this and reported to military intelligence that the embassy had complied with the Tokyo order to destroy its codes.^[30]

Also on December 3, SIS began picking the word “haruna” in messages being transmitted by the Japanese consuls in New York, New Orleans, and Havana. Its significance may not have been fully appreciated at the time, for the cable directing the Japanese embassy in Washington to cable “haruna” to Tokyo after destroying their codes and code machines had only been intercepted, decoded, and translated that very day. The next day we intercepted transmissions of “haruna” from Portland and Panama. On December 5 the Japanese consuls in Hollywood, Seattle, and Vancouver (Canada) also cabled Tokyo “haruna.” Ottawa did the same the following day.^[31]

Security of U.S. Communications in Pacific in Jeopardy

In compliance with U.S. Pacific Fleet Operating Plan, Rainbow No. Five, Admiral Kimmel had sent reinforcements to the mid-Pacific islands under his command—Wake (1,994 miles west of Pearl Harbor)^[32] and Guam (located 1,334 miles farther out in the midst of the Japanese mandated islands, 3,340 miles west of Pearl Harbor).^[33]

In Washington, toward the end of the office day on December 5, one of the women employed in the Registered Publication Section realized that the forces which had gone to Wake had taken with them a lot of registered publications. Captain Safford, who was in charge of the security section of the Navy’s Communications Division, had warned Guam the day before to destroy all “secret and classified publications and other classified matter.” Safford now became concerned about Wake; he asked the persons in the Registered Publication Section “to make a complete inventory” of the sensitive materials there. One or two officers and a couple of civilians in the Section worked on the assignment until about 1 o’clock in the morning. “[T]he next morning they gave [Safford] an inventory of 150 different registered publications on that little island where, you see, they had almost nothing” in the way of defense. “And at that time,” in Safford’s view, “war was right around the corner.”^[34]

As communications officer, Safford was responsible for safeguarding the security of our lines of communications. “Intelligence” was not within his purview; he could not convey to the field his judgment that “war was right around the corner.” However, the safety of the “registered publications” on Wake, under the jurisdiction of the Pacific Fleet, was one of his responsibilities. Therefore, Safford drafted a message for the fleet’s commander-in-chief, Kimmel, and for the information of the senior officers on Wake. “In view of imminence of war,” it read, they were to “destroy all registered publications except this system and current editions of aircraft code and direction finder code.”^[35] Before such a message could go out, it had to be approved by Safford’s superior, Admiral Noyes, director of Naval Communications. So Safford took his draft to Noyes.

Noyes: “What do you mean by using such language as that?”

Safford: “Admiral, the war is just a matter of days, if not of hours.”

Noyes: “You may think there is going to be a war, but I think they are bluffing.”

Safford: “Well, Admiral, if all these publications on Wake are captured we will never be able to explain it.”

Noyes then “rewrote the message and left out any reference to Wake Island or the 150 publications exposed to capture, which included all our reserve publications for the next six months.” The message as it was actually released, addressed to Kimmel under date of December 6, for transmission to Wake, read as follows:

In view of the international situation and the exposed position of the outlying Pacific islands you may authorize the destruction by them of secret and confidential documents now or under later conditions of greater emergency.

This “ambiguous” message was released by Assistant Chief of Naval Operations Ingersoll and sent to Kimmel at Pearl Harbor, who still had to relay it to Wake. Moreover, it “was sent deferred precedence, which meant delivery by 9:00 on Monday morning, December 8, 1941.”^[36]

British and Dutch on the Qui Vive in Southeast Pacific

By November 29, Singapore had begun to go on the alert. “[A]ll troops away from barracks . . . had been ordered back.” British Air Chief Marshall Sir Robert Brooke-Popham had “ordered the second degree of readiness, and the Volunteers were being mobilized. Soon troops were recalled from leave and other precautions were taken, including the rounding up of Japanese civilians.”^[37]

All Singapore was on the qui vive. More ships than usual were on the move. Troops were being recalled to duty. Our naval observer in Singapore, Captain John M. Creighton, was busy shuttling back and forth between his two offices, 18 miles apart. He wanted to be physically acquainted with the dockyard so that “if contingents of our fleet came there [he] could guide them to all the shops” and arrange for them “to get repairs on guns, batteries, or anything else.” He was also busy routing American merchant ships in that area. And he frequently had to arrange special passes for the many American visitors arriving at the airports with dispatches, money, and sometimes pistols, which were not always allowed into the country.^[38]

A report reached Singapore during the night of December 4 or 5 that a pilot of a British reconnaissance airplane, flying from a certain point “northeast of Malaya on a regular patrol up toward Siam . . . in the late afternoon . . . had encountered a large [Japanese] convoy of what looked to him like transports, several old battleships, an aircraft carrier, and attendant destroyers.” They were already south and west of Indochina and were “headed west and almost south of the south point of Siam. . . . [W]hen he went closer in his plane to observe them . . . Japanese fighter planes came up off the deck of the carrier and went straight at him, making it perfectly evident that they would keep him from approaching the convoy.” It was presumed that “after nightfall they would [either] continue west to the Kra Peninsula, north of Malaya, or shift northwest toward Bangkok, toward which many threats had been made recently.”^[39]

Two big British ships, Repulse, a battle cruiser, and Prince of Wales, a battleship that was undergoing repairs so as to be ready for sea duty once more, had been sent out to Singapore. Admiral Sir Tom Phillips, recently appointed commander-in-chief of the Eastern Fleet, had arrived there ahead of the ships and had flown on December 4 to Manila for a conference with Admiral Hart. Their talks “ended abruptly” with the news of the large Japanese convoy on its way from Camranh Bay towards the Gulf of Siam. “As Philllips was leaving for Singapore . . . Hart told him that he had just ordered four of his destroyers, then at Balikpapan (Borneo), to join Phillips’s force.”^[40] Phillips arrived back in Singapore on the morning of December 7 (December 6, Washington time).

The entire region was on the alert. “[B]ecause of the movement of Japanese task forces southward and possibly into the China Sea,” a conference was called in Australia early in December by Air Chief Marshall Sir Charles Burnett, chief of staff, of the Royal Australian Air Force. In attendance were representatives of the British, Dutch, and American governments—Colonel Van S. Merle-Smith, U.S. military attaché at the legation in Melbourne; Commander Salm, the Dutch Indies naval liaison officer to the Australian government; Lieutenant Robert H. O’Dell, then assistant military attaché in Australia; and Air Commodore Hewitt, the Royal Australian Air Force intelligence officer, who came and went during the conference.^[41]

“[U]pon learning of Japanese naval movements out of Palau,” one of the Caroline Islands less than 600 miles north of the Dutch East Indies, the Netherlands Far East Command had ordered on December 6 the execution of mobilization Plan A-2.^[42] War Plan A-2 was “a mutual agreement among Britain, Holland (the Indies), America and Australia” in line with the ADB conversations at Singapore in the spring of 1941.^[43]

The Australians had offered to furnish some aircraft to the Dutch. But then planes reached Koepang on the island of Dutch Timor and the Netherlands command did not consider Australian air assistance necessary. However, the Australian Air Corps chief decided to go ahead just the same and furnish the Dutch with aircraft as planned.^[44]

With respect to Thailand, or Siam, the situation was “complicated.” The Thai prime minister, “who expected an attack within the next few days—asked on December 5 for an immediate declaration” from the British that they “should go to war with Japan if the latter attacked Thailand. . . . Churchill proposed to send the Thai Prime Minister a message telling the Thais to defend themselves, if attacked, and promising to come to their aid.”^[45]

Sometime during the day, December 6, Britain’s ambassador in Washington, Lord Halifax, got in touch with Roosevelt to tell him of Churchill’s intentions to contact the Thais. “The president agreed with the [Churchill] proposal (subject to a change in wording) and said that he [FDR] intended to send a similar message. Mr. Churchill accepted the president’s formula and sent his [Churchill’s] message on the night of December 6–7.”^[46]

Admiral Hart (Manila) Learns of U.S. Commitment of “Armed Support” to British and Dutch in S.E. Asia

In Singapore, Captain Creighton learned that the United States was committed to lend “armed support” to the British or Dutch in the event that the Japanese attacked in that part of the world. He so wired Hart at 10:26 a.m. on December 6. Creighton reported to Hart that Brooke-Popham, commander of the Royal Air Force in Malaya and of the British Army Forces, had been advised on Saturday by the War Department in London that they had “now received assurance of American armed support” in three eventualities: (1) if the British were obliged to forestall a Japanese landing on the Isthmus of Kra (Malayan Peninsula), or on any other part of Siam, (2) if the Dutch Indies were attacked and the British went to their defense, or (3) if the Japanese attacked the British. Moreover, Brooke-Popham could “put plan in action [without reference to London] if you [Brooke-Popham] have good info Jap expedition advancing with apparent intention of landing in Kra second if the Nips violate any part of Thailand.” Also if the Netherlands East Indies were attacked he should put into operation the British-Dutch plans agreed upon.^[47]

Hart was dumbfounded at the news that the British had been “assured of American armed support.” He had just agreed to send four of his destroyers to join Phillips’s force. However, this news from Singapore was apparently Hart’s first intimation that the United States had a definite commitment to support the British or Dutch militarily if the Japanese should attack either of them at Thailand, the Isthmus of Kra, or the Netherlands East Indies. Any such commitment would necessarily involve the Asiatic Fleet under his command. Hart wired Washington for instructions.^[48]