ULTRA : main series of signals conveying intelligence to Allied Commands based on intercepted radio messages.
The approximately 52,000 documents were arranged and filmed by the Public Record Office of Great Britain.
Intelligence Reports
The MAGIC documents : summaries and transcripts of the top-secret diplomatic communications of Japan, 1938-1945.
The documents in the set have been filmed from the holdings of the U.S. National Archives and include messages between the Japanese Foreign Office and its key personnel and allies.