The Emperor's Codes: The Breaking of Japan's Secret Ciphers

Admittedly Michael Smith does have two important agendas in his book "The Emperor's Codes"; first to tell the largely untold saga of breaking Japanese military and diplomatic codes, and then, to emphasize the important role played by British codebreakers in unlocking these Japanese secrets. On both accounts, Smith succeeds admirably, even if he tends to dwell too much on the anecdotal first hand accounts given by some codebreakers. Smith notes that many of the most important Japanese codes were broken first by Australian and British codebreakers such as Eric Nave and John Tiltman, long before American codebreakers made significant headway in reading encrypted Japanese messages. However, he does not trivialize the important contributions American codebreakers made in this effort, though some readers may wish that Smith gave a more comprehensive overview of American achievements in codebreaking, which would prove to be far more substantial by the war's end. Nevertheless, Michael Smith has made an important contribution in emphasizing the important work done by codebreakers during the Pacific theater of World War Two, which unfortunately has been long overlooked in stark contrast to the well documented history of cracking Enigma and other Nazi codes by both British and American codebreakers.

Plenty of titles have focussed on the breaking of the Nazis' 'enigma' cipher by codebreakers; but this focus on Allied codebreakers who worked on Japanese codes provides many insights on a little-discussed subject, considering how Japan's codes were broken and how the codebreakers actually worked. This focus on both the Japan codes and the cipher breakers themselves provides a much-needed, well-rounded examination and fills in much world history.

Not an easy read, unless you're already into ciphers, but a very useful exposition of the trials and tribulations of codebreaking in a wartime setting. I'm amused that folks found it one-sided or biased. Hey, it's about the British effort, which was considerable! I thought Smith was more than fair to the American effort, which he concedes was larger and often faster. The point is: it took both British and American expertise (and contrasting attitudes) to do the job.The most valuable lesson here is that the codes (neither German nor Japanese) were never entirely broken. The codebreaker's job was almost as arduous in August 1945 as it was in November 1941. How they did their work is endlessly fascinating.

Michael Smith's book is a wonderful addition to the growing list of books dealing with code breaking during the Second World War. I was less then familar with the breaking of the Japanese codes, so I picked up this book to educate myself about an unfamilar subject. Smith's book provided a great overview of British attempts to break the Japanese codes during the war. This is not a book dealing with all of code breaking, its primary focus is on the British role. Smith's assertion is that British codebreakers did as much as Americans in breaking the Japanese codes. Not a difficult argument to imagine from an Englishman who spent a number of years working in codebreaking. Smith obviously has a bias toward the British codebreakers who came before him. That aside, the book provides wonderful detail and a number of quotes from people who were actually involved. The personal stories help bring the war to life. Occasionally it become very technical about how the codebreaking was done but all in all a good read.

The history of cracking the German codes during World War II has emerged slowly over the last ten years, and is now fairly fully described. By comparison, relatively little has been revealed about the comparable efforts aimed at Japanese codes. Recent declassification of British documents, privileged access to secret Australian histories of these events, and extensive new interviews with participants by Mr. Michael Smith (who spent 9 years in codebreaking for British Intelligence) provide the basis for the most complete and interesting account yet of the efforts aimed at Japan. The book is a success as a riveting history of individuals, for explaining the techniques involved, changing your view of how the war was won, and for raising fascinating new questions about military activities (did the atomic bomb really have to be dropped, or did Truman drop the ball?).Right after World War II, the American cryptographers broke the story of how they had cracked the Japanese diplomatic code (the so-called Purple code). What was not known, until recently, is that almost all of success with the other Japanese codes involved British and/or Australian codebreakers. Even more surprising is that the U.S. Navy kept intercepts and code books from the British codebreakers despite agreements to share. Undoubtedly, many lost their lives and the war was prolonged because of these U.S. errors. But there were also errors in using the coded output. Some commanders just wouldn't take it seriously, and placed their ships in harm's way. Consider the irony of the British decoding an impending attack on their codebreaking home in Ceylon which the British Navy largely ignored after the attack was delayed for a few days. The Japanese codebreaking was much more difficult than that for the German codes because the allies had few Japanese readers to draw on. Before the war's end, the British invented a six month cram course that effectively taught code-breaking Japanese. Also, because the British lost so many bases in Asia, the codebreakers were pushed further and further away from Japanese bases and shipping. That meant an inability to get enough radio messages to be able to effectively decode. At the key turning points in the war, the British were trying to listen to Japan from a lousy station in Kenya. Go figure! Here's where the U.S. Navy could have made a big difference, because they always had lots of intercepts from naval shipping in the Pacific. "The record of the US Navy in cooperation, not just with the British but with their own Army, was not merely lamentable, it was shameful." Interestingly, the Japanese codes were able to be broken mostly because the Japanese assumed that no one could. So when it appeared that the codes might have been compromised, they kept using the same ones. That gave the allies an edge. The Japanese also had some habits that helped. They began many messages with similar flowery language such as "I have the honour to inform