Hiroshi Ōshima

Baron Hiroshi Ōshima (大島 浩) was a general in the Imperial Japanese Army, Japanese ambassador to Nazi Germany before and during World War II — and unknowingly a major source of communications intelligence for the Allies. His role was perhaps best summed up by General George C. Marshall, who identified Ōshima as "our main basis of information regarding Hitler's intentions in Europe".

Early life
Ōshima was the son of a prominent Japanese family from Gifu Prefecture, his father Oshima Ken'ichi (大島 健一) having served as Minister of War from 1916 to 1918. Ōshima graduated from the 18th class of the Imperial Japanese Army Academy in June 1905 and was promoted to second lieutenant in June 1906 and to lieutenant in June 1908. He graduated from the 27th class of the Army War College in May 1915, and was promoted to captain the following year. From 1918-1919, he served in Siberia with the expeditionary forces, and was appointed assistant military attaché in the Japanese embassy to the Weimar Republic. Promoted to major in January 1922, he served as a military attaché to Budapest and Vienna from 1923-1924. After his return to Japan, he was promoted to lieutenant colonel in August 1926; following a promotion to colonel in August 1930, he served as commander of the 10th Field Artillery Regiment from 1930-1931.

Military career
In 1934, Colonel Ōshima became Japanese military attaché in Berlin. He spoke almost perfect German, and was soon befriended by Joachim von Ribbentrop, who was Adolf Hitler's favorite foreign policy advisor at that time. Although Hitler ostensibly used the Foreign Ministry (Auswärtiges Amt) for his foreign relations, he was in fact more dependent on the Dienststelle Ribbentrop, a competing foreign office operated by the ex-champagne salesman. Öshima's importance for Hitler during that period can be seen in the fact that following the conclusion of the Anti Comintern Pact, US Ambassador in Japan, Joseph Grew estimated that the agreement was more the result of Ōshima's work done even without the participation of the Japanese Ministry of Foreign Affairs.

Promoted to major general in March 1935, under Ribbentrop's guidance, Ōshima met privately with Hitler that fall. With the support of the Nazi leadership and the Imperial Japanese Army General Staff, Ōshima progressed rapidly while in Berlin, attaining the rank of lieutenant general and being appointed ambassador to Berlin in October 1938, upon which he entered the reserves. During his early months as an ambassador, according to evidence presented later at the Nürnberg Trial of Major War Criminals, he was plotting the assassination of Joseph Stalin through Russian agents that were sympathetic to his cause. In a conversation Ōshima had with Heinrich Himmler on 31 January 1939, he expressed the hope that German-Japanese cooperation in the field of intelligence would lead eventually to the disintegration of the Soviet Union.

In September 1939, Ōshima was recalled to Japan (with Saburō Kurusu succeeding him) - as relations between the German and Japanese governments were strained following the conclusion of the German-Soviet non-aggression pact - returning via the United States. Upon the insistence of the Nazi government, he returned to Berlin as Japanese Ambassador in February 1941, and remained in that position until the German surrender in May 1945. He dedicated his efforts until the end of the war in Europe to build closer relations between the two countries, including military cooperation in the Indian Ocean area (in the form of anti-merchant submarine warfare); thus he was instrumental in the forging and signing of the Anti-Comintern Pact on 25 November 1936 and the Tripartite Pact on 27 September 1940. Such was his fanaticism to the Nazi ideology that he created an impression in American journalist William L. Shirer, writing in his book The Rise and Fall of the Third Reich that Ōshima "is more Nazi than the Nazis".

Ōshima's close relationship with Hitler and Ribbentrop gave him unparalleled access for a foreigner to German war plans and national policy, comparable to that of Winston Churchill with the American war leadership. In turn, Hitler admired the militaristic Japanese and made Ōshima a personal confidante.

Ōshima made visits to the Eastern Front and the Atlantic Wall, and he met periodically with Hitler and other Nazi leaders. Being a meticulous military officer in training, he wrote detailed reports of the information provided to him by the Nazis — and promptly reported by radio to Tokyo in the Purple diplomatic cipher. Unknown to the Japanese, the PURPLE code was broken by American codebreakers in 1940; thus Oshima's reports were being read almost simultaneously by those who had access to Magic intelligence. Often, they were able to read them before the Japanese did, as transmission problems between Germany and Japan often held up the cables for hours.

Pacific War
Already on 13 February 1941, Ōshima discussed with Ribbentrop the possibility of a joint German-Japanese initiative for war against the British Empire and the United States, and agreeing with him the time was ripe to strike at the British Empire in Asia. On 23 February 1941, Ribbentrop urged him to press the Japanese government to attack British possessions in East Asia. On 28 November 1941, in a conversation with Ribbentrop, the German Foreign Minister, he was given an assurance that the Third Reich would join the Japanese government in case of war against the United States.

Such was Hitler's high esteem that Ōshima was one of only eight recipients of the Grand Cross of the Order of the German Eagle in Gold. Hitler awarded the medal following the attack on Pearl Harbor in 1941. The award ceremony was attended by Reich Foreign Minister Ribbentrop and the secret notes of the conference were revealed at the Nuremberg trials in 1945. In addressing Ōshima, Hitler reportedly said: "You gave the right declaration of war. This method is the only proper one. Japan pursued it formerly and it corresponds with his own system, that is, to negotiate as long as possible. But if one sees that the other is interested only in putting one off, in shaming and humiliating one, and is not willing to come to an agreement, then one should strike as hard as possible, and not waste time declaring war."

Germany presses for Japanese attack on Soviets
Despite Ōshima's anti-Soviet positions, the Japanese government in April 1941 concluded a non-aggression pact with Moscow. The German armed forces invaded the Soviet Union in June and the German government was interested in a simultaneous Japanese attack on the USSR. However, prior to the invasion itself, the German government did not update Ōshima about plans of attack. In a conversation held on 17 May 1941, Ernst von Weizsäcker, State Secretary in the German Foreign Office, denied there was any tension with the Soviet government.

Following the invasion of the USSR on 22 June 1941, pressure was placed on the Japanese government to join the invasion. On 9 July 1942, Ribbentrop tried to convince Ōshima to urge his government to join the attack on the Soviet Union. Ribbentrop's main argument being that "never again would Japan have such an opportunity as existed at present to eliminate once and for all the Russian colossus in eastern Asia". On 6 March 1943, Ōshima delivered Ribbentrop the following official statement from the Japanese government: "The Japanese Government absolutely recognize the danger which threatens from Russia and completely understand the desire of their German ally that Japan on her part will also enter the war against Russia. However, it is not possible for the Japanese Government, considering the present war situation, to enter into the war. They are rather of the conviction that it would be in the common interest not to start the war against Russia now. On the other hand, the Japanese Government would never disregard the Russian question."

Supporting war crimes
Ōshima's high esteem with Hitler made him privy to some of the planning relating to actions later to be defined war crimes and atrocities. One example was a meeting held between him and Hitler on 3 January 1942, where they both agreed on the action of sinking life-boats working for the rescue of Allied naval personnel fleeing ships sunk in military action. The official text reads: "the Führer pointed out that, however many ships the United States built, one of their main problems would be the lack of personnel. For that reason even merchant ships would be sunk without warning with the intention of killing as many of the crew as possible. Once it gets around that most of the seamen are lost in the sinkings, the Americans would soon have difficulties in enlisting new people. The training of sea-going personnel takes a very long time. We are fighting for our existence and our attitude cannot be ruled by any humane feelings. For this reason he must give the order that in case foreign seamen could not be taken prisoner, which is in most cases not possible on the sea, U-boats were to surface after torpedoing and shoot up the Lifeboats. Ambassador Ōshima heartily agreed with the Führer's comments, and said, "that the Japanese, too, are forced to follow these methods."

At a meeting Ōshima had with Hitler and Ribbentrop on 27 May 1944, Hitler advised that the Japanese government should publicly hang every captured US pilot who was involved in air raids, with the hope this would deter further such attacks.

Intercepted dispatches
Virtually all of Ōshima's dispatches were intercepted: approximately 75 during the 11 months of 1941, some 100 in 1942, 400 in 1943, 600 in 1944, and about 300 during the just over four months of 1945 when Germany was at war. For example, in a dispatch decoded on 19 January 1942, Ribbentrop agreed to supply daily intelligence reports to Ōshima, which he could pass on to Tokyo. He warned that "any leakage of these reports due to our fault would be of grave consequence, so all the handling of these reports should be strictly secret". This despite the fact that the Germans often reproached him of the unreliability of the Japanese codes, although Ōshima assured them of its security. This laxity proved to be fatal to Japanese espionage efforts, as even much of the intelligence gathered by the Japanese spy network codenamed TO in Spain (with implicit support given by the Spanish authorities) was channelled through him. This evidence halted the loading of petroleum by the United States onto Spanish tankers in 1944.

While some of his predictions were wrong — Ōshima predicted that Britain would surrender to Germany before the end of 1941 — his reporting of the Nazi leadership's plans and policies and his factual data were invaluable to the Allies. For example, on 6 June 1941, he advised Tokyo that Germany would invade the Soviet Union on 22 June (see Operation Barbarossa).

Another example was in November 1943, when Ōshima was taken on a four-day tour of the Atlantic Wall fortifications on the coast of France. Upon his return to Berlin, he wrote a detailed 20-page report of his visit, giving an account of the location of every German division, as well as its manpower and weaponry. He described tank ditches in detail, armament of turrets located close to the shore, and available mobile forces. This provided valuable intelligence to the planners of the D-Day assault. Connected to this was that the Allies knew that Operation Fortitude was working because just one week before D-Day, Hitler confided to Ōshima that while the Allies might make diversionary feints in Norway, Brittany and Normandy, they will actually open up "an all-out second front in the area of the Straits of Dover". Thus Ōshima dutifully reported that the bulk of German forces would not be waiting in Normandy, but mistakenly, at the Pas-de-Calais area.

His dispatches also proved to be valuable to those who were involved in the bombing campaign in Europe, as Ōshima provided details on the effect of Allied bombing raids on specific German targets, giving valuable and relatively unbiased bomb damage assessments to the Allies.

During and after the war
As the war progressed and Germany began to retreat, Ōshima never wavered in his confidence that Germany would emerge victorious. However, in March 1945 he reported to Tokyo on the "danger of Berlin becoming a battlefield" and revealing a fear "that the abandonment of Berlin may take place another month". On 13 April 1945, he met with Ribbentrop — for the last time, it turned out — and vowed to stand with the leaders of the Third Reich in their hour of crisis. "I do not wish to be treated in the same manner as other diplomats merely by reason of great danger from the ravages of war", he announced. But he was informed that evening by the Foreign Ministry's chief of protocol: all diplomats were to leave Berlin at once by Hitler's direct order. Ōshima had sent his wife to Bad Gastein, a mountain resort in Austria, and the next day left to join her, together with most of the Japanese diplomatic staff.

Less than a month later Germany surrendered and Ōshima and his staff were taken into custody. They were brought to the United States by ship, arriving on 11 July 1945. After interrogation and internment in Bedford Springs Hotel, a resort hotel in the heart of the Allegheny Mountains, Pennsylvania, Ōshima was returned to Japan in November 1945.

Although he enjoyed freedom briefly in his devastated country, he was arrested on 16 December 1945 and charged with war crimes. When brought before the International Military Tribunal for the Far East, he was found guilty of conspiring to wage aggressive war on 12 November 1948 and sentenced to life imprisonment. Ōshima was paroled in late 1955 and granted clemency three years later. Ōshima died in 1975, not knowing that he provided the Allies with invaluable intelligence during the war.