Tokyo in the Purple diplomatic cipher. Unknown to the Japanese, the Purple cipher was broken by American codebreakers in 1940. Thus, Oshima's reports were read almost simultaneously by his superiors in Japan and by Allied leaders and analysts as "Magic" intelligence. Sometimes, the Allies read the reports before the Japanese did, as transmission problems between Germany and Japan often held up the reports for hours. Ōshima was interviewed in 1959 and asked about the security of his transmissions. He said that he had been warned in 1941 by Heinrich Georg Stahmer that there were signs that Japanese diplomatic messages were being read by the Allies, but that he was convinced that, by double-encrypting his dispatches, he had ensured they could not be decrypted by the Allies. He died before the Allied decryption of Purple messages became common knowledge and so never knew that he had unwittingly provided the Allies with priceless intelligence. Pacific War On 13 February 1941, Ōshima discussed the possibility of a joint German-Japanese initiative for war against the British Empire and the United States with Ribbentrop, 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 German Foreign Minister, Ōshima was given an assurance that Nazi Germany 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 15 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: Germany presses for Japanese attack on Soviets Despite Ōshima's anti-Soviet positions, the Imperial 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 had not updated Ōshima about plans of attack. In a conversation held on 17 May 1941, Ernst von Weizsäcker, State Secretary in the German Foreign Office, denied that there