THE CODEBREAKERS Page 6

  On the afternoon of April 28, Hans Thomsen, counselor of the German embassy in Washington, cabled his Foreign Ministry, in a message not read by the U.S.: “As communicated to me by an absolutely reliable source, the State Department is in possession of the key to the Japanese coding system and is therefore also able to decipher telegrams from Tokyo to Ambassador Nomura here regarding Ambassador Oshima’s reports from Berlin.” After thinking about it for a few days, Berlin gave this information to its Axis ally through Baron Hiroshi Oshima, the Japanese ambassador to Germany. He passed it to Tokyo on May 3 in a cable saying he believed it, and Tokyo, on May 5, asked Washington “whether you have any suspicion” of the matter. The American codebreakers, who had been following the Japanese messages from Berlin to Tokyo to Washington, held their breath. They remembered how Japan had canceled her J12 code in 1940 on her first inkling that the British and Dutch were reading it. But Nomura’s reply—“The most stringent precautions are taken by all custodians of codes and ciphers”—evidently soothed the Foreign Office, for it contented itself with issuing stricter regulations for coding.

  Then, on May 20, Nomura told Tokyo: “Though I do not know which ones, I have discovered the United States is reading some of our codes.” The cryptanalysts shuddered. Would they have to start all over again? Nothing happened at once, but a few days later an incident made it appear that only the shipment of new systems from Japan was delaying the change of codes. On May 30, Japan prohibited her merchant vessels all over the world from further use of Code S. More to the point, she did so less than 24 hours after she learned that U.S. narcotics agents had removed codes from the tanker Nichi Shin Maru near San Francisco during a search.

  The dreaded change of code, which would have cost the United States her best source of information just as it was needed more and more, now seemed inevitable. But morning after morning, the messages bore the same aspect and continued to break down under the same treatment. After days of anxious waiting, Navy cryptanalysts read a cable from Tokyo to Mexico on June 23, warning the legation: “There are also some suspicions that they [the Americans] read some of our codes. Therefore, we wish to exercise the utmost caution in accomplishing this mission.”

  Was this to be the extent of the Japanese security precautions? It seemed incredible, yet it appeared so. The cryptosystems continued unchanged. The Foreign Office capped its ludicrous cryptosecurity program of pointless warnings and regulation changes with a step that was almost as effective as the others: on November 25, it directed its embassies to print “Kokka Kimitsu” (“State Secret”) in red enamel on the right of the number plate of their cipher machines. Perhaps they thought that this incantation would prevent cryptanalysis as an amulet was supposed to ward off sickness!

  But if the Foreign Office discredited the rumors of solution (because, in its natural pride, it could not imagine its codes being anything but impregnable), the American recipients of MAGIC knew that they were all too true. In 1939, the director of naval intelligence had personally brought MAGIC in a looseleaf folder to a recipient, waited there while he read it, then took the folder on to the next recipient. The increasing volume of MAGIC had slowly eaten away at this original iron security. Colonel Rufus S. Bratton, chief of the Far Eastern section of Army intelligence, found himself wasting so much time chaperoning his single copy that he began to have duplicates and triplicates made. The number of copies grew from 4 in early 1941 to 14 by December. Subordinates assumed the time-consuming messenger function. Kramer took over for the Navy. Bratton, who had a higher rank and more responsibilities than Kramer (his opposite number was Kramer’s superior, McCollum), had to delegate some of this work still further. Three assistants in the Japan subsection of his Far Eastern section, Lieutenant Colonel Carlisle C. Dusenbury, Major Wallace H. Moore, and Second Lieutenant J. Bayard Schindel, made some of his rounds for him. Instead of carrying around a single folder, copies were left with the recipient.

  Marshall saw danger in all this: “I intervened very directly and required that it [MAGIC] be locked in a pouch and delivered by pouch, the pouch unlocked and it be read by the recipient and put back in the pouch.” The “pouches” were actually zippered briefcases made by the Washington leather shop of Becker & Co. Each had a padlock to which there were only two keys, one held by the disseminator, one by the recipient, either personally or by his aide. This crackdown—about September—compelled the executive officer of the military intelligence division, who had been seeing MAGIC while his chief was on leave, to surrender his key and to stop reading the intercepts. The Navy soon adopted the Marshall precautions. Kramer, for example, often sat next to the recipient and explained references, furnished background, answered questions, and so forth—which is why so valuable an officer was given the apparently menial messenger task. Nevertheless, departures from this ideal occurred. The messenger could not very well stand over the Secretary of War or the Chief of Naval Operations while the messages were being read. In the State Department, the pouch was actually left overnight and exchanged the next day for a new one.

  Still, the documents circulated in a cloud of mystery and continuous precaution. When Kramer telephoned in advance to recipients to find out where they were before delivering the intercepts, he would say only guarded words like, “I have something important that you should see.” Bratton’s immediate superior frequently saw him “leave his office with several parcels under his arm and be gone for several hours,” and, because he knew that his superior wanted it that way, never asked about it. He also received packages from S.I.S. chief Minckler when Bratton was out; these he locked up in his safe and turned over to Bratton on his return without having looked into them. Before MAGIC was given to State, Army and Navy officers met with Hull to explain how a loose word could suddenly extinguish the light shed by these intercepts. When Knox received the documents at his apartment, he did not explain them to his wife. At high-level conferences, recipients took care not to mention MAGIC when men not privy to the secret attended. All copies had to be returned. No recipient could retain them for reference, though back copies were sometimes included in new folders when later messages referred to them. The cryptanalytic agencies each filed two copies, one by date, one by subject, and the Far Eastern sections of Army and Navy intelligence each kept one. All other copies were burned.

  Before an intercept could even begin the rounds that would end in this fiery immolation, it ordinarily had to be translated, and translation was the bottleneck of the MAGIC production line. Interpreters of Japanese were even scarcer than expert cryptanalysts. Security precluded employing Nisei or any but the most trustworthy Americans. The Navy scoured the country for acceptable translators, and through prodigious efforts in 1941 it doubled its GZ translation staff—to six. These included three whom Kramer called “the most highly skilled Occidentals in the Japanese language in the world.”

  But ability in standard Japanese alone did not suffice. Each translator had to have at least a year’s experience in telegraphic Japanese as well before he could be trusted to come through with the correct interpretation of a dispatch. This is because telegraphic Japanese is virtually a language within a language, and, as McCollum, himself a Japanese-language officer, explained, “the so-called translator in this type of stuff almost has to be a cryptographer himself. You understand that these things come out in the form of syllables, and it is how you group your syllables that you make your words. There is no punctuation.

  “Now, without the Chinese ideograph to read from, it is most difficult to group these things together. That is, any two sounds grouped together to make a word may mean a variety of things. For instance, ‘ba’ may mean horses or fields, old women, or my hand, all depending on the ideographs with which it is written. On the so-called translator is forced the job of taking unrelated syllables and grouping them into what looks to him to be intelligible words, substituting then such of the Chinese ideographs necessary to pin it down, and then going ahead with the translation, which is a much more di
fficult job than simple translation.”

  Hence the situation of Mrs. Dorothy Edgers. She had lived for thirty years in Japan and had a diploma from a Japanese school to teach Japanese to Japanese students up to high-school level. Yet, because she had only two weeks’ experience in GZ at the time of Pearl Harbor, Kramer considered her “not a reliable translator” in this field. And on the important messages, only reliable translators could be used. To unclog this bottleneck, messages in the minor systems were given only a partial translation. If a translator saw that they dealt with administrative trivia, they were frequently not formally translated at all.

  With manifold streamlinings like that, with enlarged staffs, with the fluidity gained by experience, OP-20-G and S.I.S. gradually increased the speed and quantity of their output. In 1939, the agencies had often required three weeks to funnel a message from interceptor to recipient. In the latter part of 1941 the process sometimes took as little as four hours. Occasionally an agency broke down a late intercept that bore on a point of Japanese-American negotiations and rushed it to the Secretary of State an hour before he was to meet with the Japanese ambassadors. Volume attained overwhelming proportions. By the fall of 1941, 50 to 75 messages a day sluiced out of the two agencies, and at least once the quantity swelled to 130. Some of these messages ran to 15 typewritten pages.

  The top-echelon recipients of MAGIC clearly could not afford the time to read all this traffic. Much of it was of secondary importance anyway. Kramer and Bratton winnowed the wheat from this chaff. Reading the entire output, they chose an average of 25 messages a day for distribution. At first Kramer supplemented his translations with gists for recipients too busy to read every word of the actual intercepts, starring the important ones, but he abandoned these in mid-November under the pressure of getting out the basic material. Bratton, who had been delivering summaries of MAGIC in the form of Intelligence Bulletins, began on August 5 to distribute MAGIC verbatim at Marshall’s orders. This, however, had the effect of increasing the volume. Marshall complained that to absorb every word of it he would have had to “retire as Chief of Staff and read every day.” To save the recipients’ time, Bratton checked the important messages on a list in the folder with a red pencil; Kramer slid paper clips onto them. The recipients always read the flagged messages; the others they did not always read thoroughly, but they did leaf through the folder and skim them.

  Distribution was usually made twice a day. Intercepts that had come in overnight went out in the morning, those processed during the day went out at the end of the afternoon. Especially important messages were delivered at once, often to the recipients’ homes if late in the evening. Each agency sent its MAGIC copies on to the other with exemplary promptitude, despite a natural competition between them. As Bratton put it: “I was further urged on by the fact that if the Chief of Naval Operations ever got one of these things before General Marshall did and called him up to discuss it on the telephone with him, and the General hadn’t gotten his copy, we all caught hell.” (Marshall demurred: “I don’t think I gave anybody hell much.”)

  Delivery to the White House and the State Department incurred difficulties. Under the January 23 agreement, the Army and Navy at first alternated in servicing the two. The Army, however, discontinued its deliveries to the White House after its turn in May, partly because of Watson’s wastebasket security bungle, partly because it felt that these diplomatic matters should go to the President through the State Department. The Navy continued its deliveries through the President’s naval aide, Captain John R. Beardall, though once in the summer Kramer himself carried a particularly “hot” message—probably dealing with negotiations the next day—to Roosevelt. Near the end of September, a month originally scheduled for Army delivery, during which nothing was delivered to the White House, the President said he wanted to see the intercept information. In October naval intelligence sent him memoranda based on MAGIC, but on Friday, November 7, Roosevelt said he wanted to see MAGIC itself. Beardall told him that it was an Army month. The President replied that he knew that and that he was either seeing MAGIC or getting information on it from Hull, but that he still wanted to see the original intercepts. He feared that condensing them would distort their meaning. On Monday, a conference agreed that the Navy would furnish the White House with MAGIC and the Army the State Department. At 4:15 p.m., Wednesday, November 12, Kramer made the first distribution to the White House under this system.

  Thus, by the fall of 1941, MAGIC was being demanded at the topmost level of government. It had become a regular and vital factor in the formation of American policy. Hull, who looked upon MAGIC “as I would a witness who is giving evidence against his own side of the case,” was “at all times intensely interested in the contents of the intercepts.” The chief of Army intelligence regarded MAGIC as the most reliable and authentic information that the War Department was receiving on Japanese intentions and activities. The Navy war plans chief thought that MAGIC, which was largely diplomatic at this time, affected his estimates by about 15 per cent. The high officials not only read MAGIC avidly and discussed it at their conferences, they acted upon it. Thus the decision to set up the command of United States Army Forces, Far East, which was headed by General MacArthur, stemmed directly from intercepts early in 1941 showing that Germany was pressuring Japan to attack Britain in Asia in the hope of involving the United States in the war; on the basis of this information, the command was created in July to deter Japan by enhancing American prestige in the Western Pacific—and it is a fact that Japan did not then comply with Germany’s wishes.

  The intricate mechanism of the American cryptanalytic effort pumped MAGIC to its eager recipients smoothly, speedily, and lavishly. Messages flew back and forth along the COPEK channel as if along nerve cells. Intercepts poured into Washington with less and less of a time lag. S.I.S. and GY grew increasingly adept at solution; the translators picked out the important messages ever more surely. Bratton and Kramer hustled from place to place with their locked briefcases, MAGIC gushed forth in profusion. So effectively did the cryptanalytic agencies perform that Marshall could say of this “priceless asset,” this most complete and up-to-the-minute intelligence that any nation had ever had concerning a probable enemy, this necromantic gift of the gods of which one could apparently never have enough, that “There was too much of it.”

  In October the cabinet of Prince Konoye fell, and the Emperor summoned General Hideki Tojo to form a new government. One of the first acts of the new Foreign Minister, Shigenori Togo, was to call in the chief of the cable section. Togo, remembering a book that Herbert O. Yardley had written disclosing his 1920 solution of Japanese diplomatic codes, asked the cable chief, Kazuji Kameyama, whether their current diplomatic communications were secure. Kameyama reassured him. “This time,” he said, “it’s all right.”

  With the assumption of total power by the militarists under Tojo, the last real hopes for peace died. Almost at once, events began to slide toward war. On November 4, Tokyo sent to her ambassadors at Washington the text of her proposal B, which Togo described as “absolutely final.” The ambassadors held it while they pursued other avenues, even though Tokyo, on November 5, told them that “Because of various circumstances, it is absolutely necessary that all arrangements for the signing of this agreement be completed by the 25th of this month.”

  That same day, Yamamoto promulgated Combined Fleet Top Secret Order Number 1, the plan for the Pearl Harbor attack. Two days later, he set December 8 (Tokyo time) as Y-day and named Vice Admiral Chuichi Nagumo as Commander, First Air Fleet—the Pearl Harbor strike force. In the days that followed, the 32 ships that were to compose the force slipped, one by one, out to sea and vanished. Far from any observation, they headed north to rendezvous in a bay of barren Etoforu Island, one of the chill, desolate Kuriles north of the four main islands of Japan. Behind them the ships left their regular wireless operators to carry on an apparently routine radio traffic in their own “fists,” or sending touch, which is
as distinctive as handwriting.

  As the force was gathering, the Foreign Office, which knew only that the situation was tense and was never told in advance of the time, place, or nature of the planned attack, prepared an open-code arrangement as an emergency means of notification. Tokyo sent Circular 2353 to Washington on November 19:

  Regarding the broadcast of a special message in an emergency.

  In case of emergency (danger of cutting off our diplomatic relations), and the cutting off of international communications, the following warning will be added in the middle of the daily Japanese language short-wave news broadcast:

  In case of Japan-U.S. relations in danger: HIGASHI NO KAZE AME (“east wind rain”)

  Japan-U.S.S.R. relations: KITA NO KAZE KUMORI (“north wind cloudy”)

  Japan-British relations: NISHI NO KAZE HARE (“west wind clear”)

  This signal will be given in the middle and at the end as a weather forecast and each sentence will be repeated twice. When this is heard please destroy all code papers, etc. This is as yet to be a completely secret arrangement.

  Forward as urgent intelligence.

  This open code related the winds to the compass points in which the named countries stood in regard to Japan: the U.S. to the east, Russia to the north, England to the west. Tokyo also set up an almost similar code for use in the general intelligence (not news) broadcasts.

  As the secret messages establishing these open codes whistled through the air, Navy intercept Station S at Bainbridge Island heard and nabbed them. The station teletyped them to GY, which identified them as J19 and began cryptanalysis.

  Many of the ships of the Pearl Harbor strike force had by then gathered in bleak Tankan Bay, where the only signs of human presence were a small concrete pier, a wireless shack, and three fishermen’s huts. Snow covered the surrounding hills. In the gray twilight of November 21, the great carrier Zuikaku glided into the remote harbor to complete the roster. The force swung at anchor, awaiting the order to sortie.