KOBE -- In mid-1941, as tensions between Japan and the United States mounted, Washington took extreme precautions to protect coded diplomatic messages between the U.S. Embassy in Tokyo and the State Department from being intercepted by the Japanese.
The conventional wisdom after the war was that U.S. efforts had been successful. But a chance discovery by two young scholars at Kobe University earlier this year shows that Japan was decoding messages sent during the crucial months before the attack on Pearl Harbor, and experts now say that history will have to be rewritten.
Toshihiro Minohara, an assistant professor at Kobe University, and Satoshi Hattori, a lecturer, announced that documents discovered in the Foreign Ministry's archives show clearly that the Japanese government had broken secret codes used not only by the United States but also Britain, China and Canada.