THE CODEBREAKERS
Page 7
A few hours later, on November 20 (Washington time), the Japanese ambassador to the United States, Admiral Kichisaburo Nomura, and his newly arrived associate, Saburo Kurusu, presented Japan’s ultimatum to Hull. It would have required the United States to reverse its foreign policy, acquiesce in further Japanese conquests, supply Japan with as much oil as she required for them, abandon China, and in effect surrender to international immorality. While Hull began drafting a reply, Tokyo cabled its ambassadors in message 812 that “There are reasons beyond your ability to guess why we wanted to settle Japanese-American relations by the 25th, but if within the next three or four days you can finish your conversations with the Americans; if the signing can be completed by the 29th (let me write it out for you—twenty-ninth); if the pertinent notes can be exchanged; if we can get an understanding with Great Britain and the Netherlands; and in short if everything can be finished, we have decided to wait until that date. This time we mean it, the deadline absolutely cannot be changed. After that things are automatically going to happen.” Two days later, Togo wirelessed: “The time limit set in my message No. 812 is in Tokyo time.”
The calendar had become a clock, and the clock had begun to tick.
On November 25, Yamamoto ordered the Pearl Harbor strike force to sortie next day. At 6 a.m. on November 26, the 32 ships of the force—six carriers, two battleships, and a flock of destroyers and support vessels—weighed anchor and sliced across the wrinkled surface of Tankan Bay. They steamed slightly south of east, heading into the “vacant sea”—the wintry North Pacific, whose wastes were undefiled by merchant tracks and whose empty vastness would swallow up the force. They had been ordered to return if detected before December 6 (Tokyo time); if discovered on December 7, Nagumo would decide whether or not to attack. Strict radio silence was enjoined. Aboard the battleship Hiei, Commander Kazuyoshi Kochi, a communications officer for the force, removed an essential part of his transmitter and put it in a wooden box, which he used as a pillow. The force drove eastward through fog, gale winds, and high seas. No one saw them.
Meanwhile, Hull, after a frantic week of drafting, consultations, and redraftings, had completed the American reply to Japan’s proposal. It called upon Japan to withdraw all forces from China and Indochina and in return promised to unfreeze Japanese funds and resume trade. Nothing was said about oil. On November 26, the day that he handed it to Nomura and Kurusu, a message came from Tokyo setting up an open code for them for telephone use to speed up their reports. In it, the President was MISS KIMIKO, Hull was MISS FUMEKO, Japanese-American negotiations were to be referred to as a MARRIAGE PROPOSAL, the criticality of the situation as the imminence of the birth of a child, the China question as SAN FRANCISCO, and so on. They had occasion to use it the very next night to report on an interview with Hull. Kurusu talked for seven minutes, starting at 11:27 p.m. Washington time, with Kumaicho Yamamoto, the chief of the American bureau of the Japanese Foreign Office.* American interceptors had their recording machine running even before the Japanese started theirs, and succeeded in capturing even this rare form of communication. Kramer translated the conversation, interpreted the rather amateurish application of the open code (even detecting an attempt to bolster it with some extraneous comments), added the colorful description of vocal nuances and pauses, and distributed it with the routine MAGIC intercepts the following day.
[Secret]
From: Washington
To: Tokyo
27 November 1941 (2327-2334 EST)
(Telephone Code)—(See JD-1: 6841) (S. I. S. #25344)
Trans-Pacific
Telephone
(Conversation between Ambassador Kurusu and Japanese Foreign Office American Division Chief, Yamamoto.)
Literal translation Decode of Voice Code
(After connection was completed:)
KURUSU: “Hello, hello. This is Kurusu.”
YAMAMOTO: “This is Yamamoto.”
KURUSU: “Yes, Hello, hello.”
(Unable to get Yamamoto for about six or eight seconds, he said aside, to himself, or to someone near him:)
KURUSU: “Oh, I see, they’re making a record of this, huh?”
(It is believed he meant that the six-second interruption was made so that a record could be started in Tokyo. Interceptor’s machine had been started several minutes earlier.)
KURUSU: “Hello. Sorry to trouble you so often.”
YAMAMOTO: “How did the matrimonial question get along today?” “How did the negotiations go today?”
KURUSU: “Oh, haven’t you got our telegram† yet? It was sent—let me see—at about six—no, seven o’clock. Seven o’clock. About three hours ago.
“There wasn’t much that was different from what Miss Fumeko said yesterday.” There wasn’t much that was different from Hull’s talks of yesterday.”
Literal translation Decode of Voice Code
YAMAMOTO: “Oh, there wasn’t much difference?”
KURUSU: “No, there wasn’t. As before, that southward matter—that south, SOUTH—southward matter, is having considerable effect. You know, southward matter.”
YAMAMOTO (Obviously trying to indicate the serious effect that Japanese concentrations, etc. in French Indo-China were having on the conversations in Washington. He tries to do this without getting away from the “Miss Fumeko childbirth, marriage” character of the voice code.):
YAMAMOTO: “Oh, the south matter? It’s effective?”
KURUSU: “Yes, and at one time, the matrimonial question seemed as if it would be settled.” “Yes, and at one time it looked as though we could reach an agreement.”
KURUSU: “But—well, of course, there are other matters involved too, but—that was it—that was the monkey wrench. Details are included in the telegram* which should arrive very shortly. It is not very long and you’ll be able to read it quickly.”
YAMAMOTO: “Oh, you’ve dispatched it?”
KURUSU: “Oh, yes, quite a while ago. At about 7 o’clock.”
(Pause.)
KURUSU: “How do things look there? Does it seem as if a child might be born?” “Does it seem as crisis is at hand?”
YAMAMOTO (In a very definite tone): “Yes, the birth of the child seems imminent.” “Yes, a crisis does appear imminent.”
KURUSU: (In a somewhat surprised tone, repeating Yamamoto’s statement:)
“It does seem as if the birth is going to take place?” “A crisis does appear imminent?”
(Pause.)
KURUSU: “In which direction …”
(Stopped himself very abruptly at this slip which went outside the character of the voice code. After a slight pause he quickly recovered, then to cover up the slip, continued:)
KURUSU: “Is it to be a boy or a girl?”
YAMAMOTO (Hesitated, then laughing at his hesitation took up Kurusu’s cue to reestablish the voice code character of the talk. The “boy, girl, healthy” byplay has no other significance.):
YAMAMOTO: “It seems as if it will be a strong healthy boy.”
KURUSU: “Oh, it’s to be a strong healthy boy?”
(Rather long pause.)
Literal translation Decode of Voice Code
YAMAMOTO: “Yes.”
“Did you make any statement (to the newspapers) regarding your talk with Miss Kimiko today?” “Did you make any statement regarding your talks with the President today?”
KURUSU: “No, nothing. Nothing except the mere fact that we met.”
YAMAMOTO: “Regarding the matter contained in the telegram‡ of the other day, although no definite decision has been made yet, please be advised that effecting it will be difficult.”
KURUSU: “Oh, it is difficult, huh?”
YAMAMOTO: “Yes, it is.”
KURUSU: “Well, I guess there’s nothing more that can be done then.”
YAMAMOTO: “Well, yes.”
(Pause.)
YAMAMOTO: “Then, today …”
KURUSU: “Today?”
YAMAMOTO: “
The matrimonial question, that is, the matter pertaining to arranging a marriage—don’t break them off.” “Regarding negotiations, don’t break them off.”
KURUSU: “Not break them? You mean talks.”
(Helplessly:)
KURUSU: “Oh, my.”
(Pause, and then with a resigned laugh:)
KURUSU: “Well, I’ll do what I can.”
(Continuing after a pause:)
KURUSU: “Please read carefully what Miss Kimiko had to say as contained in today’s telegram.”† “Please read carefully what the President had to say as contained in today’s telegram.”†
YAMAMOTO: “From what time to what time were your talks today?”
KURUSU: “Oh, today’s was from 2:30.”
(Much repeating of the numeral 2.)
KURUSU: “Oh, you mean the duration? Oh, that was for about an hour.”
YAMAMOTO: “Regarding the matrimonial question.” “Regarding the negotiations.”
“I shall send you another message. However, please bear in mind that the matter of the other day is a very difficult one.”
KURUSU: “But without anything,—they want to keep carrying on the matrimonial question. They do. In the meantime we’re faced with the excitement of having a child born. On top of that Tokugawa is “But without anything,—they want to of keep on negotiating, In the meantime we
Literal translation Decode of Voice Code
*† JD-1: 6915 (S. I. S. #25495). Outline of interview on November 27 with Roosevelt-Hull-Kurusu-Nomura.
‡ Probably #1189 (S. I. S. #25441-42). (JD-1:6896). Washington reports the two proposals presented by the U.S. on November 26.
really champing at the bit, isn’t he? Tokugawa is, isn’t he?” have a crisis on hand and the army is champing at the bit. You know the army.”
(Laughter and pause.)
KURUSU: “That’s why I doubt if anything can be done.”
YAMAMOTO: “I don’t think it’s as bad as that.”
YAMAMOTO: “Well,—we can’t sell a mountain.” “Well,—we can’t yield.”
KURUSU: “Oh, sure, I know that. That isn’t even a debatable question any more.”
YAMAMOTO: “Well, then, although we can’t yield, we’ll give you some kind of a reply to that telegram.”
KURUSU: “In any event, Miss Kimiko is leaving town tomorrow, and will remain in the country until Wednesday.” “In any event, the President is leaving town tomorrow, and will remain in the country until Wednesday.”
YAMAMOTO: “Will you please continue to do your best.”
KURUSU: “Oh, yes. I’ll do my best. And Nomura’s doing everything too.”
YAMAMOTO: “Oh, all right. In today’s talks, there wasn’t anything of special interest then?”
KURUSU: “No, nothing of particular interest, except that it is quite clear now that that southward—ah—the south, the south matter is having considerable effect.”
YAMAMOTO: “I see. Well, then, good-bye.”
KURUSU: “Good-bye.”
25443
JD-1: 6890 (M) Navy Trans. 11-28-41 ( )
The same day that this conversation was held, Tokyo circularized its major embassies with still another open code. While the winds code envisioned abolition of all communication with the embassies, this new code—called the INGO DENPO (“hidden word”) code—was intended for a less critical situation. It seems to have been arranged at the request of the consul in Singapore in case code but not plain language telegrams were prohibited. It set up such equivalences as ARIMURA = code communications prohibited; HATTORI = relations between Japan and (name of country) are not in accordance with expectation;* KODAMA = Japan; KUBOTA = U.S.S.R.; MINAMI = U.S.A.; and so on. “In order to distinguish these cables from others,” Tokyo said, “the English word STOP will be added at the end as an indicator. (The Japanese word OWARI [end] will not be used.)”
The next day, November 28, the Navy cracked the transposition for the J19 message of nine days earlier and learned of the winds code arrangement. The cryptanalytic agencies saw at once that this arrangement, which dispensed with the entire routine of coding, cabling, delivery, and decoding, could give several hours’ advance warning of Japan’s intentions. They erupted into activity to try to intercept it. This wrenched facilities away from the commercial (for Japanese diplomatic), naval, and radiotelephone circuits with which the agencies were familiar and put them on voice newscasts.
The Army asked the Federal Communications Commission to listen for the winds code execute. Army stations at Hawaii and San Francisco tuned to the newscasts, as did Navy stations at Corregidor, Hawaii, and Bainbridge Island, and four or five along the Atlantic seaboard. Rochefort placed his four best language officers—Lieutenants Forrest R. Biard, J. R. Bromley, Allyn Cole, Jr., and G. M. Slonim—on a 24-hour watch on frequencies suggested by Washington and on others that his unit had found. The Dutch in Java and the British in Singapore listened. In Washington, Kramer made up some 3 × 5 cards for distribution to MAGIC recipients. They bore only the portentous phrases, “East Wind Rain: United States. North Wind Cloudy: Russia. West Wind Clear: England.”
Soon plain-language intercepts were swamping GZ. Bainbridge ran up bills of $60 a day to send them in. Kramer and the other translators, already burdened, now had also to scan 100 feet of teletype paper a day for the execute; previously only three to five feet per week of plain-language material had come in. The long strips were thrown into the wastebasket and burned after checking. Several times the GY watch officers telephoned Kramer at his home at night to ask him to come to the office and check a possible execute. It always proved false.
Meanwhile, other signs of increasing tension were not lacking. On the 29th, Baron Oshima in Berlin reported that the German Foreign Minister, Joachim von Ribbentrop, had told him, “Should Japan become engaged in a war against the United States, Germany, of course, would join the war immediately.” Next day, Tokyo replied, “Say very secretly to them that there is extreme danger that war may suddenly break out between the Anglo-Saxon nations and Japan through some clash of arms and add that the time of the breaking out of this war may come quicker than anyone dreams.” Both these messages were translated on December 1, and Roosevelt considered the latter so important that he asked for a copy of it to keep. Kramer, after paraphrasing it for security’s sake, gave him one.
At Pearl Harbor, Rochefort had just been presented with an unpleasant confirmation of that tautening situation. The Japanese fleet reassigned its 20,000 radio call-signs at midnight, December 1—only 30 days after the previous change. It was the first time in Rochefort’s experience that a switch had occurred so soon after a previous one.
The one on November 1 had been expected; it had followed by the usual six months the regular spring call-sign shift. With the facility born of long experience, Rochefort’s Combat Intelligence Unit identified in fairly rapid order the senders and receivers of a large percentage of the traffic. The unit observed the rising volume and southward routing of messages on the 200 radio circuits of the Japanese Navy. This fitted in almost perfectly with the widely known Japanese buildup for what the world thought was a strike at Siam or Singapore. By the third week in November, the unit had sensed the formation of a Third Fleet task force and its imminent departure in the direction of those areas. Aircraft carriers were not addressed during this buildup, nor did they transmit. To Rochefort, the situation shaped up like those of February and July, when Japanese fleet units moved south to support the takeover in French Indochina while the carriers remained in home waters as a reserve. They were there, he felt, to protect the exposed flank of the Japanese forces from the American fleet, which, from its bases at Cavite and Pearl, could sever the supply lines of the aggressor.
Rochefort’s view was shared by fleet intelligence officer Layton. He knew that the two main carrier divisions had not appeared in the traffic for at least two weeks, and maybe three. He suspected their presence in home waters, but since he lacked positive indications
of it, he omitted his presumptions from a report on the Japanese fleet that he submitted to Kimmel on December 1. Whereupon, Layton recalled:
Admiral Kimmel said, “What! You don’t know where Carrier Division 1 and Carrier Division 2 are!”
I replied, “No, sir, I do not. I think they are in home waters, but I do not know where they are. The rest of these units, I feel pretty confident of their location.” Then Admiral Kimmel looked at me, as sometimes he would, with somewhat a stern countenance and yet partially with a twinkle in his eye, and said:
“Do you mean to say that they could be rounding Diamond Head and you wouldn’t know it?” or words to that effect. My reply was that “I hope they would be sighted before now,” or words to that effect.
On the same day that Layton gave his report to Kimmel, the Office of Naval Intelligence produced a memorandum of “Japanese Fleet Locations” that Layton, when he saw it, considered as “dotting the i’s and crossing the t’s” of his own estimates. It placed Akagi and Kaga (Carrier Division 1), and Koryu and Kasuga in southern Kyushu waters, and Soryu and Hiryu (Carrier Division 2) and Zuikaku, Shokaku, Hosho, and Ryujo at the great naval base of Kure. All this was just a more precise way of saying “home waters.”
These estimates were based on the November observations. The call-sign change of December 1 obliterated the intricate communication networks that the radio intelligence units had so painstakingly built up and forced them to begin anew. The Japanese bedeviled them with new communication-security measures. Dispatches were sent “on the umbrella”—broadcast to the fleet at large and copied by all ships. This sort of blanket coverage made identification difficult. Multiple addresses were used. They sent dummy traffic, which, however, did not confuse the listeners. Just before the change, the communicators passed many old messages. Rochefort’s unit spotted them, and guessed that they were attempts either to pad the volume or to get through to the addressee before the change caused routing difficulties.