Kozo Izumi and the Soviet Breach of Imperial Japanese Diplomatic Codes

摘要

Japan's diplomatic codes were broken by the Soviet Union in the late 1930s. This was due to Kozo Izumi (1890-1956), a Japanese diplomat and Soviet specialist stationed in Eastern Europe, who provided Japan's code books and keys to the Soviet secret police. Married to a Muscovite of noble origin working for the Soviet Foreign Intelligence, Izumi was entrapped and ultimately chose love over country. He thus led an unwitting Japan to conduct 'open diplomacy' towards the Soviet Union.