Baron was a Japanese general in the Imperial Japanese Army and diplomat. He served as the Japanese ambassador to Germany before and during World War II and was, unwittingly, 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". After World War II, he was convicted of war crimes and sentenced to life imprisonment, but was paroled in 1955. Biography Early life Ōshima came from a provincial low-ranking samurai family from Gifu Prefecture. His father was a known Germanophile, a trait the future ambassador to Berlin would inherit, who nevertheless rose up the ranks and eventually served as Army Minister from 1916 to 1918, ironically waging war against Imperial Germany. Much was thus expected of the young Ōshima and his rise in the Imperial Army structure was swift. He graduated from the Imperial Japanese Army Academy in June 1905, the 18th of his class, and was promoted to second lieutenant in June 1906, then 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 to 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 to 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 to 1931. Military and diplomatic career In 1934, Colonel Ōshima became Japanese military attaché in Berlin. He spoke almost perfect German, and was soon befriended by Joachim von Ribbentrop, then Adolf Hitler's favourite foreign policy advisor. Although Hitler ostensibly used the Foreign Ministry (Auswärtiges Amt) for his foreign relations, he was actually more dependent on the Dienststelle Ribbentrop, a competing foreign office operated by the ex-champagne salesman. Ōshima was 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. He attained the rank of lieutenant general and