The Emperor’s Codes: Bletchley Park and the Breaking of Japan’s Secret Ciphers

The extraordinary wartime exploits of the British codebreakers based at Bletchley Park continue to fascinate and amaze.

In his bestselling Station X Michael Smith brought us the astonishing true story of the breaking of the Enigma Cipher. In The Emperor’s Codes he continues the story as he examines how Japan’s codes were broken, and the consequences for the Second World War.

The Emperor’s Codes moves across the world from Bletchley Park to Pearl Harbor; from Singapore to Colombo; and from Mombasa to Melbourne, describing not just how the Japanese codes and ciphers were broken but how the lives of the codebreakers, both professional and personal, were affected. It tells the stories of John Tiltman, the eccentric British soldier turned codebreaker who made many of the early breaks into Japanese diplomatic and military codes; Eric Nave, the Australian sailor recruited to work for the British who pioneered breakthroughs in Japanese naval codes; and of Oshima Hiroshi, the hard-drinking Japanese ambassador to Berlin, whose candid reports to Tokyo of his conversations with Hitler and other high-ranking Nazis were a major source of intelligence in the war against Germany. Many of these revelations have been made possible only through using recently declassified British files, through privileged access to Australian secret official histories, and interviews with an unprecedented number of British, American and Australian codebreakers.

Where previous books on the subject have emphasised the role played by the Americans, The Emperor’s Codes is the first full account of the critical role played by British and Australian codebreakers. Using the memories of those at the forefront of this battle, Michael Smith reveals a gripping and previously untold story from the Second World War.