Pearl Harbor: From Infamy To Greatness

by Craig Nelson

  Yamamoto ordered Vice Admiral Mitsumi Shimizu, commander in chief, Sixth Fleet, to lead his submarines as part of the First Air Fleet’s Kido Butai (mobile force), saying on July 29, “Under present conditions I think war is unavoidable. If it comes, I believe there would be nothing for me to do but attack Pearl Harbor at the outset, thus tipping the balance of power in our favor.”

  Shimizu would commandeer a large force of twenty-five fleet and five midgets—a high percentage of the sixty-three subs in the entire Japanese fleet—whose assignments would include reconnaissance, interception of American reinforcements, attacking ships attempting to sortie from the anchorage, and rescuing downed pilots. The midgets were ordered to penetrate the harbor and torpedo any warships that had escaped the First Air Fleet’s bomb and torpedo strikes. Japan had used midget submarines before, but those had been launched from surface ships; they now modified fleet submarines to ferry the midgets to within ten miles of Pearl Harbor. There, the midgets’ size would let them stealthily cruise into Pearl’s lochs, lurk beneath the surface of her shallow waters, then rise to attack American warships.

  The midgets were all of seventy-eight feet long, weighed forty-six tons, and were armed with two torpedoes powerful enough to bring down a battleship. Crewed by two men operating from a control room the size of a coat closet with internal temperatures spiking at 150 degrees, they had a range of eighty miles surfaced and eighteen submerged. During the nights of their voyage when the mother subs surfaced, the crewmen could inspect their charges. In the rocking seas, they were roped to the ship with safety harnesses, and twice, Ensign Kazuo Sakamaki was pulled overboard by waves and had to be hauled back aboard.

  Theoretically the crews of the midget subs had a chance to survive their mission, but no one—least of all the crews themselves—harbored illusions about the odds against these tiny craft escaping through Pearl Harbor’s narrow channel in the aftermath of the attack. Ensign Sakamaki, who will be the sole survivor of the ten crewman, summed up their predicament: “None of us was a volunteer; we had all been ordered to our assignment. That none of us objected goes without saying. We knew that punishment would be very severe if we objected; we were supposed to feel highly honored.”

  • • •

  In the middle of January 1941, Peru’s ambassador to Japan, Ricardo Rivera-Schreiber, heard a rumor that made him go directly to the American embassy and on January 27, Ambassador Grew cabled his revelation to the State Department: “My Peruvian colleague told a member of my staff that he had heard from many sources including a Japanese source that the Japanese military forces planned, in the event of trouble with the United States, to attempt a surprise mass attack on Pearl Harbor using all of their military facilities. He added that although the project seemed fantastic the fact that he had heard it from many sources prompted him to pass on the information.”

  On February 1, 1941, Chief of Naval Operations Harold Stark cabled this news to Commander in Chief of the Pacific Fleet Husband Kimmel, and then said, “The Division of Naval Intelligence places no credence in these rumors. Furthermore, based on known data regarding the present disposition and employment of Japanese Naval and Army forces, no move against Pearl Harbor appears imminent or planned for in the foreseeable future.” Kimmel replied that he was making defensive plans anyway, since “I feel that a surprise attack (submarine, air, or combined) on Pearl Harbor is a possibility. We are taking immediate practical steps to minimize the damage inflicted and to ensure that the attacking force will pay.”

  In February, a squadron of Japanese warships arrived in the Gulf of Siam, with Tokyo claiming its purpose was to resolve border clashes between French Indochina and Thailand. American diplomats in Japan warned the vice minister of foreign affairs that if Japan threatened the British, it “would have to expect to come into conflict with the United States.” A shocked official asked for clarification: “Do you mean to say that if Japan were to attack Singapore, there would be war with the United States?” Embassy counselor Eugene Dooman replied, “The logic of the situation would inevitably raise that question.” On February 6, Roosevelt threatened that if Japan attacked the Soviets, the United States would have to intervene. On the seventh, an irritated Matsuoka asked for a straight-up answer: Was the United States ready to fight?

  • • •

  Over the course of the following months, President Roosevelt met at least five times with his admirals to explore sailing an expeditionary force to Europe. Though America would become the powerhouse arsenal of democracy for the Allied cause in a mere eighteen months, at that moment she lacked the men, transports, and warships needed for such a vast undertaking. In January of that year, US factories produced 159 bombers and 248 fighters, which were divvied out as seventy-seven to the US Navy; fifteen to the US Army; and 315 to the United Kingdom. It wasn’t bad, but it wasn’t enough to beat Hitler.

  On February 14, Japanese ambassador Nomura met with Hull and Roosevelt at the White House. The president bought up his and Nomura’s “association of some twenty-odd years ago” and asked if, instead of ambassador, could the president call him admiral? FDR went on to say that the United States and Japan “were friends that could at all times talk candidly as friends about the relations and the related affairs of the two countries,” but present relations were “deteriorating,” and that if Hull and Roosevelt “had not almost instantly played down the Panay incident, there would in all probability have been a terrific inflammation of public sentiment in this country.”

  On February 25, Stark forwarded to Kimmel his analysis of the situation in Southeast Asia. As the US Department of War had determined that Japan didn’t have enough men or ships to invade French Indochina, Thailand, British Singapore, and the American Philippines simultaneously, Stark concluded that Japan could only strike the British, the Dutch, and the American territories one at a time, meaning Tokyo posed little threat to US interests at that moment.

  In early March, perhaps linking Taranto with the Peruvian rumor in his thoughts, Marshall asked Short what defenses Pearl Harbor had against carrier-based torpedo planes. The answer was convoluted, because in Hawaii, the Department of War had the army’s troops guarding the navy’s fleet when it was anchored at Pearl Harbor. Yet, the army’s Hawaiian Department chief of staff, Colonel Walter Phillips, would later testify, “We felt secure against a raid, particularly with the Fleet here.” The Army Air Corps was to additionally coordinate short-range aerial surveillance while the navy performed long-range scouting, but Phillips said, “I never knew what the navy had [in its scout-plane arsenal].” Similarly, the army man in charge of defending the navy’s ships at harbor, General Walter Short, said that the Fleet, as well as the bases of Wake and Midway, were a far more formidable defense than his troops would ever be.

  On March 8, Cordell Hull, with his speech impediment, had his first long-running one-on-one conversation with Ambassador Nomura, whose English was less than fluent and who was partially deaf. Hull and Nomura would meet fifty times over the next nine months, with Hull telling colleagues that the Japanese were notoriously two-faced, and nothing they said could be trusted.

  To begin their dialogue, Hull asked Nomura if the military groups running Japan expected the United States “to sit absolutely quiet while two or three nations before our very eyes organized naval and military forces and went out and conquered the balance of the earth, including the seven seas and all trade routes and the other four continents”? Nomura replied that he didn’t think Japan would make any further military moves unless American embargoes forced its hand. When on March 14, Hull and Nomura met again with FDR at the White House, “The Ambassador proceeded to say [that] none of his people, with few exceptions, desired war between our two countries,” Hull noted; “that Matsuoka talks loudly for home consumption because he is ambitious politically, but Japan herself cannot maintain such ambitious plans.” The president “proceeded to emphasize vigorously the dangerous effects of this [Tripartite] agreement and the utter lack of any sou
nd reason for Japan to enter into it from every standpoint of her welfare. The Ambassador rather lamely remarked that this country was pressing Japan with embargoes and trade restrictions, and they were in a way forced into this Tripartite arrangement.”

  Though American armed forces weren’t ready for a global conflict, Washington had a remarkable secret weapon that no Axis leader in Tokyo, Rome, or Berlin knew anything about. The weapon had been born on Friday, September 20, 1940, when thirty-two-year-old Frank Rowlett arrived at his job at DC’s Munitions Building an hour early, as he did every workday. He was allowed past the steel gate and armed guards to his offices in rooms 3416 and 3418, guarded and gated since Rowlett was a civilian in charge of the team trying to break the code of the highest level of Japan’s diplomatic ciphers.

  This was all part of a remarkable history, in that America had historically been poor in spy talent, but rich in code breakers. After the Versailles accords, the US Army continued to run an intelligence unit specializing in aerial photography (and, in time, radar). Backed by money from the army and State, Herbert Yardley then began a secret government program of diplomatic code-cracking in the autumn of 1919—the Black Chamber—which gave American diplomats an edge in negotiations with Japan in the Washington Conference of 1921–22. In 1923, American naval intelligence agents rifling though the luggage of a Japanese officer stationed in New York found the Secret Operating Code cookbook used by Japan’s navy in the Great War. When the American navy’s Research Desk used it to decrypt Japanese traffic, they kept the results in red folders to indicate their top-secret status, and the broken codes within were called RED.

  Believing that “gentlemen do not read each other’s mail,” Herbert Hoover’s Secretary of State Henry Stimson canceled the Black Chamber’s funding in 1929, but the efforts continued at the Department of War, where an Army Signal Intelligence Service team was cracking code after code, while the Office of Naval Intelligence Research Desk at OP-20-G monitored radio traffic and ship positions across the Pacific. At least three times during this era, ONI arranged to “borrow” ciphers from Japan’s New York consulate, but when in 1930 the Japanese changed their codes, it took two years for the navy’s operation to crack them. Keeping with tradition, they called it BLUE.

  In 1938, when Japan changed her code again, ONI hired a cryptanalyst abandoned by State, the onetime music and mathematics teacher Agnes “Miss Aggie” Meyer Driscoll. By learning the names of every major ship and frequently used phrases of Japan’s forces and paging through a photographic reproduction of the codebook’s pages with the tip of her pencil’s eraser, Miss Aggie cracked the code, now called BLACK.

  One cracker explained his craft’s eureka breakthroughs: “It first off involved what I call the staring process. You look at all of these messages that you have; you line them up in various ways; you write them one below the other; you’d write them in various forms and you’d stare at them. Pretty soon you’d notice a pattern; you’d notice a definite pattern between these messages. This was the first clue.”

  On March 20, 1939, the Americans intercepted a new Japanese diplomatic cryptosystem, and by the summer it had so replaced RED and BLACK that little traffic could be read. Frank Rowlett was in charge of breaking this new code, and on that September 20, 1940, a twenty-six-year-old cryptanalyst, Genevieve Grotjan, unlocked what Washington would call PURPLE. Rowlett took notes: “Grotjan enters room, obviously excited, politely interrupts, asks if she can show us what she has found. She takes us to her desk in next room, lays out worksheets, points to one example, then another, then a third. She stands back, with eyes tranced behind her rimless glasses. Small dashes around the room, hands clasped above his head like a victorious prizefighter. ‘Whoopee!’ he yells. Ferner, the quiet one, clasps his hands, shouting, ‘Hooray, Hooray.’ I jump up and down—‘That’s it! That’s it!’ The room gets crowded; everyone in section suddenly in room. Friedman comes in and asks, ‘What’s all the noise about?’ I settle down and say, ‘Look what Miss Grotjan has just discovered.’ Gene wipes her eyes, tries to regain her composure. I point to the worksheets—‘Gene’s found what we’ve been looking for. Look here, and here, and here.’ ”

  Once again, a woman who would remain unrecognized by her country had delivered a behind-the-scenes breakthrough that would lead to victory in World War II. As countless American nerd geniuses would do in decades to come, the team celebrated their great achievement by ordering in bottles of Coke.

  Before Pearl Harbor, anyone with ambitions for a high-ranking career in the US military avoided intelligence, which was universally dismissed as a desk job for those lacking in courage. Before PURPLE, any intelligence cooperation between the US Army and Navy was more a matter of individual initiative than of concerted policy. Now, Japan’s consular cables were intercepted by military listening stations in Alaska, Washington State, Hawaii, Guam, and Luzon, as well as collected at the cable companies’ offices, except for many years in Honolulu, where intercepting cables was judged illegal.I The intercepted messages were forwarded to Washington, frequently by mail, and then decoded, translated, and evaluated by army and navy intelligence. Those results went to the navy’s Rear Admiral Richmond Kelly Turner and the army’s Brigadier General Leonard T. Gerow, who selected the most significant for a locked briefcase, carried daily by a distributing officer to the secretaries of navy, war, and state; the army’s chief of staff; the chief of naval operations; and the president. Each US official read the decoded and translated materials with the officer standing by, then returned the documents to G-2, where they were burned.

  By the fall of 1941, American cryptographers would know about Japan’s foreign policy before its ambassadors to America (a situation that would be echoed at war’s end when Stalin knew more about the development of the atomic bomb than Truman). It was so astonishing that someone—many swear it was FDR—called it magic, and MAGIC was and remains one of the few joint operations between the American army and navy that worked well, with an astonishing 97 percent success rate. In one more example of FDR’s passion, he arranged for only the navy to deliver his MAGIC to the White House—never the army.

  A leak occurred in April of 1941, with information revealed by MAGIC passed over to Britain’s ambassador, who then transmitted it in a code the Nazis had cracked. On May 5, the Foreign Ministry cabled Nomura, “According to a fairly reliable source of information it appears almost certain that the United States Government is reading your code messages. Please let me know whether you have any suspicion of the above.” As Nomura was a former chief of the Intelligence Bureau of the Naval General Staff, he knew better than most consuls how to safeguard his nation’s secrets. He replied that his office took “the most stringent precautions” to protect “codes and ciphers, as well as other documents” and requested “any concrete instance or details which may turn up.” On May 20, Nomura confirmed to Tokyo, “Though I do not know which ones, I have discovered the United States is reading some of our codes. As for how I got the intelligence, I will inform you by courier or another safe way.”

  We don’t have further details on how Nomura learned about American codebreaking, but since the Foreign Office did not recalibrate its codes after the leak, the United States kept reading them. Unfortunately, just as the Japanese believed wholeheartedly that PURPLE could never be decrypted, American military chiefs believed MAGIC told them everything they needed to know about Japan. Despite MAGIC’s magic, it never found a message specifically detailing an attack on Hawaii because the Japanese foreign office never sent such a message . . . the Japanese military made sure to keep its greatest secrets away from the foreign office. Instead, when it came to potential Japanese military targets in the Pacific, the American War Plans Division had to speculate about a three-thousand-mile geographic area ranging from the borders of Siberia to the shores of Thailand. Except for a limited number of cables that will be discussed below, nothing about Pearl Harbor was ever found in PURPLE.

  MAGIC was also less than magic
al in that its information suffered delays, given the military’s security decision to transport top-secret documents by air, sea, trucks, and trains instead of by wireless. Plus, the overwhelming need to keep MAGIC secret greatly reduced its effectiveness. Harold Stark believed, in one example, that Husband Kimmel had a PURPLE machine at Pearl Harbor, when, instead, the commander in chief of the Pacific Fleet knew nothing at all about MAGIC or PURPLE. In fact, Grew, Kimmel, and Short all lacked direct evidence of the growing Japanese menace since they had been refused clearance for MAGIC. But even if they had been part of the select few reading decrypts, MAGIC was frankly not all that useful in helping American defense forces prepare for the great Japanese assault across East Asia. Douglas MacArthur’s PURPLE machine did nothing to help him successfully defend his Philippines, and those Washington insiders who daily knew MAGIC’s revelations would be just as surprised by December 7 as Kimmel and Short.

  Additionally, the Americans had no idea that starting in 1936 the Imperial Japanese Army’s intelligence had been decoding much of America’s own diplomatic communications traffic. The IJA had cracked all three of the US State Department’s codes—the Gray, the Brown, and the Strip Cipher (which was remarkable, as neither the British nor the Germans had been able to crack that Strip Cipher). But neither Washington nor Tokyo had succeeded in cracking each other’s military codes. During their between-the-wars lull, the US Army’s Signal Intelligence Service couldn’t get enough intercepts to crack Japanese army messages, and by December 1941, with Miss Aggie and Lieutenant Prescott Currier leading the efforts, the navy had only revealed about 10 percent of the 1939 Japanese Fleet General Purpose System (which the Americans called, in turn, JN-25 and JN-25b).II