The critical information that sealed the fate of Nazi Germany came from a team of fewer than six young civilians crowded in a small room in a ramshackle government building a few blocks from the White House.

The youngest who called himself a mathematician had just finished high school; another was a graduate student in love with the Japanese language but had never visited Japan. Together they cracked the Japanese diplomatic code and deciphered the daily reports of Japan’s ambassador in Berlin sent to Tokyo. A committed Nazi and a retired general, Baron Hiroshi Oshima was a darling of German leaders, probably the only foreigner Adolf Hitler trusted. Oshima spent several days visiting the fortifications the Germans built to block an Allied invasion. Apparently, the Germans withheld nothing from him and he reported everything to his government.

The American, British and Canadian soldiers who waded ashore in Normandy on 6 June 1944 had no idea that their top commanders had in their hands an amazingly detailed and accurate blueprint of German defences and military strategy. Oshima’s reports secured the success of the landing that the best experts in the world had considered suicidal.

The civilian US team deciphered the electronically intercepted reports, secretaries typed up an English translation, and a soldier assigned to guard the team hand- delivered the envelope to President Franklin Delano Roosevelt just a few hours after they were cabled from Berlin to Tokyo. FDR authorised the delivery of copies to ten top American officials: chiefs of staff of the various military services, the head of the intelligence bureau, and the Secretary of State. FDR ordered them to burn every single page upon reading the text – and they did. They were also made to take an oath that they would never disclose the identity of the improbable source of the reports. They all followed the order with the conspicuous exception of George C. Marshall, the wartime Army Chief of Staff who became Secretary of State under FDR’s successor, Harry Truman. But the news media ignored Marshall’s brief reference to Oshima.

Oshima died many years later without knowing that unwittingly he had given away the most sensitive German secrets.

The file containing translations of the intercepted cables was declassified in the late 1990s and their story was published in The Washington Post on 26 May 1998 under this writer’s byline. Along with millions of pages of World War II intelligence reports, the original documents, replete with Roosevelt’s exclamation points and underlined phrases and even a few comments about their importance, were made available for reading at the National Archives in College Park, Maryland. This writer delivered the most important Xerox copies of the documents to The Washington Post as evidence required by the editors.


A few weeks later senior archivist John E. Taylor phoned me to find out if I kept any of my Xerox copies of the documents. It so happens that I did not. I called The Post in case they did. But my editor said that of course The Post trashed its copies of the supporting documents, as usual after the newspaper published the article that made use of them.

Taylor, the highly respected top archivist who had alerted me to the declassification of the Oshima documents, asked me to come over to the Archives as soon as possible. He waited for me at the gate and took me to a conference room for a private conversation. His voice trembled as he told me that the file that contained Oshima’s reports had disappeared. “For your information, the whole file was stolen”, he roared. “STOLEN! Somebody took every single page of the file, a very serious federal offence. A crime has been committed! Imagine: a critical wartime file is missing from our collection. Unfortunately, we neglected to make Xerox copies which we usually do shortly after declassification. We had about eight million pages to Xerox after the CIA suddenly dumped on our National Archives more than 90 per cent of its World War II files. They say it is up to 99 per cent, but I am sceptical.”

Taylor, a student of US government procedures as well as Japanese culture, recalled the extraordinary procedures that Roosevelt ordered to protect the Oshima file. “FDR worried about the Japanese reaction”, Taylor said. “But I don’t believe in the healing power of keeping silence.”

Taylor assured me that I was not under suspicion of stealing the file as the Archives records showed that I returned the file properly at the end of the day – as did a few scholars who rushed to take a quick look at the documents after The Washington Post broke the story of their existence.

Taylor was furious, as were all his colleagues. He said that the thief must have acted for “nationalist reasons”. If the reports are missing, he said, barely able to control his voice, the reports did not exist and the Americans did not break the Japanese code. “That is how many Japanese think”, he concluded and expressed his certainty that the original documents will never be found. “I bet the Japanese thieves burned them”, he added.

He also asked me to consider all his remarks off the record as long as he lives. The official line of the National Archives was that the file, registered as “For White House Interest”, was “misplaced”. “What a lie”, Taylor grumbled.


In November 1943 the US War Department learned from the intercepted cables all it needed to know about German forces stationed along the Atlantic coast from Brittany to Belgium. The level of specificity was astounding. Oshima accounted for every division’s location, manpower and weaponry. For instance, he described tank ditches as “built in a triangular cross section with a span across the top of 5 metres and a depth of 3.5 metres”, and the observation turrets as “built in a continuous line, close to the shore”, each equipped with two or three machine-guns as well as grenades. “Were the enemy successful in a partial landing”, Oshima noted, “lateral shell fire from the neighbouring posts and the appearance of mobile forces would annihilate them”. He praised the plan he called “Germany’s conception of the defence of the West”. He gave the Allies “almost zero chance” of a successful breakthrough.

Oshima described the German objective as aimed “to attain the maximum effect from a minimum number of soldiers performing defence work” in camouflaged bunkers on the shore. He was impressed with the offensive part of the strategy: “the facility of advancing directly to a counter-attack of the powerful German Reserves, who can rally with lightning speed”.

So, the Allied commanders knew what to do. As the landing began, so did a massive air and naval bombardment of the area to the rear of the coastal fortifications. According to official figures, more than 10,000 American and British planes and 80 warships participated.

Five days later, Oshima quoted Wehrmacht officers acknowledging that because of the unprecedented intensity of the bombardment, they were unable to move troops and equipment from the rear to the front, as planned. By 2 August 1944, Oshima reported to Tokyo that “the First American Army penetrated the Saint-Lô area to Avranches”, which the Germans considered “a serious situation” and rightly so.

Oshima provided detailed and accurate data on the updating of old submarines (which he claimed was his idea endorsed by Hitler), damage caused by Allied air raids, the dangerous state of the German economy (he told the Germans to employ more foreign labour which they declined, fearful of sabotage), military production figures and advances in poison gas technology (he predicted that the Germans will not use gas, fearful of British retaliation in kind).

In one brief cable, Oshima also reported to Tokyo what the Germans told him about their European allies. He learned that Hungarian Prime Minister Miklós Kállay was “a traitor” and contrasted him with the reliability of Romania’s leader who was “faithful” to the Axis.


Japan’s ambassador in Berlin since 1938, Oshima was an intimate of Nazi leaders. They trusted him more than they trusted any of their allies. Fluent in German, he was a former army general and served first in Berlin as military attaché who championed the cause of an ever-closer coordination with Hitler’s Reich. He built a network of contacts with Germany’s political, military and industrial leaders. His report on the German fortifications on the Atlantic coast summed up a four- day tour, during which he and three embassy staffers were, as he phrased it, “wined and dined” and “got the chance to talk with the right people everywhere”.

But Oshima was not an American agent. The Post headline called him an “unwitting spy”.

His reports – well-informed, richly detailed, and at times surprisingly objective for an unabashed admirer of the Nazis – were dutifully telegraphed to the foreign office in Tokyo, after a cipher clerk encrypted them, using a different number for each word.

Archivist Taylor who read the intercepted cables the day they were declassified was certain that Oshima was “our number one source”.

Americans in the Signal Intelligence Agency had broken Japan’s diplomatic code several months before the attack on Pearl Harbor on 7 December 1941, Taylor said. The military and naval codes were more complex, and their decipherment took a few more months, according to Sam Snyder, whose job description was “mathematician” though he qualified only after the war. But he was a genius in math. When I was lucky enough to track him down in 1998, he was 86 years old and he was happy to talk to an outsider about the great adventure in his youth.

“American leaders often had the opportunity to read the intercepts only two hours after they were sent”, said Snyder, who recently died in a retirement home in Rockville, a Washington suburb. “We gave them good, clean copies with no more than a word or two missing sometimes, thanks to the extensive network of US listening stations and the excellence of the decoding machine we built in Washington – and thanks to our linguist who knew Japanese real well.”

Snyder chuckled when remembering how pleased he and his colleagues were every time they realised from the cable traffic that American leaders read the messages first, and their Japanese counterparts in Tokyo had to wait for hours because of transmission problems. “We were a good team, proud of our work and especially our speed in delivering it to the President”, he said in an interview, which, he noted, was the first time he ever discussed with an outsider his secret assignment in the old Munitions Building on Constitution Avenue, across from the Federal Reserve, torn down years ago to enlarge the Mall.


Oshima offered a unique view of Hitler’s state of mind, General George Marshall wrote in an “eyes-only” letter to Republican presidential candidate Thomas Dewey on 25 September 1944, but printed in newspapers after Dewey’s defeat. George Marshall, then Army Chief of Staff and later Secretary of State, wrote to Dewey that “our main basis of information regarding Hitler’s intentions in Europe was obtained from Baron Oshima’s messages from Berlin”. Except for that letter to Dewey, Marshall was “paranoid” about keeping the intercepts secret, Taylor said.

However, Marshall’s half-a-sentence, buried in a 1,500-word text focused on Pearl Harbor, generated no news media follow-up at a time when war crime trials and European reconstruction were the top stories. “Marshall’s words were quickly forgotten”, Prof. Carl Boyd of Old Dominion University in Norfolk, Virginia, told me. “The Japanese paid no attention to the reference to Oshima – and neither did us scholars.”

Military historian Boyd wrote a scholarly biography of Oshima, titled Hitler’s Japanese Confidant, published in 1993. Working from a small number of summarised or sanitised documents declassified up until the early 1990s, he summed up Oshima as the man who knew “the precious truth about an otherwise unfathomable matter: how Hitler’s forces would react to the invasion”. But Boyd characterised Oshima’s giving away the details of German strategy on the Atlantic coast “news to me. Big news”.

Boyd’s reaction was echoed by Prof. Donald Cameron Watt of the London School of Economics, a leading British historian. “We have only known that what Oshima reported on the thinking of the German high command and Hitler was of enormous value to the Allies”, he told me. Asked how Oshima’s reports might have contributed to success in Normandy, Watt said that “it is difficult to separate the importance of different intelligence reports received by the Allies. But, certainly, Oshima provided very, very valuable information. The Allies did not have an agent in Germany of Oshima’s importance. No. No one was comparable to Oshima.”

Watt said Oshima was “the Germans’ pet”, and his value to the Allies came from the fact that “the Germans were indiscreet with him”.

Since the publication of Boyd’s book – until then the only detailed biography of Oshima – hundreds of Japanese diplomatic intercepts have been declassified in their entirety. They make up the bulk – and the cream – of the file labelled “For White House Interest” which was distributed daily to the president and ten other officials, all of them military except for the Secretary of State. Usually marked “Top Secret Ultra” – the highest level of US government secrecy at the time – they are part of the bonanza of World War II secret files, now an overwhelming total of what archivists estimate is more than 20 million pages.

“Intercepts provide a highly reliable source of intelligence”, said Donald Jameson, then a retired senior CIA officer. “You can pick up from a spy what someone said. But an intercept eliminates one level of distortion. You don’t have to count on your spy being an accurate reporter on what for example an ambassador said. An intercept of what an ambassador himself reported has the highest quality of authenticity.” Jameson cautioned that if the other side suspects its code was compromised, it may generate messages to spread misinformation. “But that was not the case with the Japanese”, he added. “It looks like we had good communications intelligence, which can be the very best intelligence there is.”

Neither Japanese nor Germans officials thought it possible that their codes could be cracked. Post-war Allied interrogations suggest that only Hitler suspected such a security catastrophe, in one of his paranoid depressions toward the war’s end.

Except when his Nazi sympathies swayed his judgement – as for instance in predicting that the Germans will repulse a landing in France – Oshima’s reports pass the test of time. For example, in instant analyses of the failed July 1944 coup against Hitler, Oshima dismissed the notion of a military insurrection or an impending civil war – both widespread Allied expectations at the time. But he accurately predicted the bloody revenge Hitler would take, even on people unconnected with the attempt.

Prof. Boyd credits Oshima for giving the outside world the first conclusive evidence concerning the July plot. (The recently declassified material includes a long list of the suspected conspirators and their roles.) Surprisingly, Oshima defended the plotters as people “who would not have made contact with enemy countries and have brought about an internal collapse in the German rear”. He went as far as contending that “the ideas of the rebel group proceeded from patriotic motives”.

After the Normandy landing, Oshima’s reports lost their optimistic bounce. On 18 August he warned Tokyo that “even the Germans have ceased to give an explanation of the new turn in the war situation”, and he observed that very few German commentators seemed “to harbour any hopes for the future”.

On 5 September 1944 Oshima presented a sombre picture of his meeting with Hitler. In reporting to Tokyo Hitler’s answers to his suddenly pugnacious questions, Oshima did not make his usual bow to the Fuhrer’s “fighting spirit”. Nor did he offer any hint of what he made of Hitler’s pledge of “a large-scale offensive in the West”.

Oshima asked Hitler if Germany could hold the current defensive line until the western offensive is launched. Hitler conceded that first more German withdrawals will take place. When Oshima asked about plans to counter the Allies’ round-the-clock bombardment of Germany, which he thought imminent, Hitler did not argue. Instead, he claimed that German anti-aircraft units were constantly increasing in number. To navy analysts in the Pacific Strategic Intelligence Section writing a study on Japanese–German relations in January 1945, the meeting had one meaning: “the Japanese practically tell the Germans that their situation is hopeless”.

On 26 September Oshima cabled that in France, the German army “crumbled”, having lost 500,000 men since June, and “the situation has taken an extremely acute turn”. He predicted the invasion of Germany. “The German army is now a forlorn and isolated force, struggling against an enemy which is closing in on it from 4 sides”, Oshima wrote. “The presentratio of tank strength is one German tank to seven enemy tanks. … Unless some miraculous expansion takes place in the near future, I cannot help but feel that Germany will soon no longer have any strength left with which to hurl back the enemy.” Oshima forecast “surrender piecemeal”, by isolated groups.

Roosevelt marked some of the paragraphs with a thick red line on the margin, suggesting its importance. (All the intercepts released to the National Archives are the originals typed in blue ink by the decoders’ stenographers, archivist Taylor explained. They were filed first by the War Department and later by the National Security Agency. On the top and bottom of each page, “TOP SECRET ULTRA” is printed in black, highlighted in yellow.)

Oshima’s description of a defensive, dejected Hitler and his army on the verge of surrender contributed to the overconfidence of the top Allied command that Germany was no longer capable of launching a counter-offensive. That is the view of British historian Watt and his American colleague Boyd.

In a recently declassified US military study completed in 1977, titled “The Battle of the Bulge”, Lt. Col. Harry L. Dull, Jr singled out “the mindset among senior US commanders” as responsible for the initial Allied setbacks in that battle in December 1944, which historians rate as the war’s worst Allied intelligence failure. Opaquely, Dull concluded: “The failure was not strictly one of lack of information, although that played a part. It was one of interpretation of the information available.”

In the course of my interview historian Boyd suggested that “Oshima’s 180 degree turn in evaluating the German army represented one reason the German attack was a surprise to the Allies”.

Dull did not discuss the influence of the Japanese intercepts on “the mindset among senior US commanders”. Most likely, Taylor said, Dull could not find any reference to the intercepts in the documents he studied; nor could anyone else. In his 1991 book titled Peace without Hiroshima, wartime US intelligence officer Martin Quigley wrote that all those who were given copies of the Japanese intercepts had to burn them after receipt and were ordered never to refer to their existence.

Retired CIA officer Jameson, who was in the Navy in the Pacific during the war, recalled that in fighting Japan, intercepts played a larger role than any other source of intelligence. He cited the example of the historic US victory at Midway Island, based entirely on intercepts. “In the European war, there were lots more inputs from other sources of intelligence”, he said, “but there, too, much greater credit was attached to intercepts. Oshima’s cables were almost certainly the major factor contributing to the top commanders’ euphoria in the fall of 1944, especially because other intelligence sources were in agreement”.

However, total reliance on one uniquely situated source also led to a disaster. Expecting Hitler to remain as passive as Oshima eventually described the man he originally idolised, Allied commanders were stunned by the German offensive in early December that led to 80,000 American casualties. It was the worst mistake of American strategic planning – a case of over confidence that plagued US policies in Asia after World War II.

Nevertheless, Allied air superiority and the Wehrmacht running out of petrol turned the Battle of the Bulge. By the end of January 1945, the Allies recaptured the territory the Germans had gained earlier, and the Luftwaffe received a death blow. German casualties totalled 120,000. Hitler lost his last, desperate gamble.

After the fall of Berlin, Oshima was repatriated to Japan where the International Military Tribunal sentenced him in 1946 to life imprisonment for his part in “the conspiracy against peace”. Historians have identified him as the architect of the Berlin–Tokyo Axis.

In 1955, he was paroled. Boyd, who corresponded with him, told me that Oshima died in obscurity in 1975, at age 89, without knowing that the Allies had intercepted his reports. “But he would not believe that an American could learn the classical Japanese he mastered”, he said.

US archivist Taylor said that Japanese visitors to the National Archives still insist that the Americans captured Japan’s code-books rather than employed technicians who broke the code. “They look down on us Americans.”

Taylor thought that the State Department was in error in ignoring the Japanese refusal to accept facts about World War II. “We have nothing to lose when reminding the Japanese of their crimes and grievous mistakes”, he told me. “They ought to be made to face reality.” He warned that the Japanese public may gradually deny the war crimes and bully its neighbours.


Shortly after my story appeared in The Post, a representative of Japan’s leading daily Mainichi Shimbun invited me for lunch. A most courteous gentleman, he congratulated me on the article on Oshima and asked if his paper could publish it, along with answers to a few questions he prepared. I agreed as the copyright for my article reverted to me. He paid me in cash. I went home, answered his questions, and sent off the piece that evening.

He thanked me next morning but a few days later he phoned me and invited me for lunch again. I could tell from the strained tone of his voice that my article ran into trouble with his editors in Tokyo. He said that his editor and publisher decided against running the article because their readers would refuse to believe that the Americans had broken the Japanese code. He said that he disagreed with his bosses one hundred percent and apologised profusely for their decision. He said he believed my American sources were truthful and as a Japanese journalist he believed in facts, not illusions. But Japanese culture has attitudes that may take a long time to change – if they ever will. “Japan is Japan”, he said when we said goodbye to each other. “And some of our people do not believe that Japan really lost the war.”

A frequent visitor to Japan told me recently that it is best to avoid discussing their country’s part in World War II with Japanese people. “Many of them are militarists in their hearts though they do not say so to Americans”, he said. “They think of themselves as a superior race and they are waiting for someone to revise their part in World War II. Shinzo Abe, their current Prime Minister, may do so one day.”

In fact, even in our days, Japan’s number one newspaper would not publish a report on the intercepted cables because its readers would not believe the unpleasant truth: a little team of American mathematicians without college degrees broke the code the Japanese believed that no foreign genius could break. The Japanese could not accept the idea that an unknown American who had never been to Japan but loved the Japanese language and culture translated the aristocratic ambassador’s reports, written in an ornate literary style he was so proud of.

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