The Emperor's Codes: The Breaking of Japan's Secret Ciphers [Hardcover]

Michael Smith (Author)

Book Description

Publication Date: June 11, 2001

From Pearl Harbor on December 7, 1941, whose devastating loss was due in large measure to our inability to decode messages about the forthcoming attack, to the Battle of Midway, code-breaking played a key role in the Pacific war. Moving across the world from Bletchley Park outside London to Pearl Harbor, from Singapore to Colombo, from Mombassa to Melbourne, The Emperor's Code reveals how the Japanese codes - of which there were several - were broken, and we discover in detail who were the (often quirky) geniuses behind the desperate effort. Unlike the German codes, where similarities of language made decrypting at least possible, the vast differences between English and Japanese made this far more daunting.

Editorial Reviews

From Library Journal

During World War II, British and American cryptographers labored in tight security at Bletchley Park and elsewhere, poring over thousands of intercepted Japanese and German military messages. This fascinating story has been told and retold over the past 15 years as more new information emerges. Smith, a British journalist and author of Station X: Decoding Nazi Secrets, has now expanded on the subject with this well-written account of how the Americans with a great deal of help from British codebreakers cracked the Japanese codes. Smith portrays the sometimes bitter competition between American naval and British military personnel and insists that the British deserve a greater share of the credit than the Americans have been willing to grant. All in all, it makes a great story and one of importance, since many historians believe that through their codebreaking efforts the Allies were able to shorten the war by as much as two years. Libraries should add Smith's book to other recent works, including Stephen Budiansky's Battle of Wits (LJ 9/15/00) and Leo Marks's Between Silk and Cyanide (LJ 4/15/99). Recommended for most collections. Ed Goedeken, Iowa State Univ. Lib., Ames
Copyright 2001 Reed Business Information, Inc.

From Booklist

The Allied efforts that led to the breaking of Germany's Enigma code have been well publicized. Less well known but equally critical to the war effort was the combined British-American success at breaking the various Japanese codes. Smith, a journalist who has worked for the London Sunday Times and the Daily Telegraph, writes a real-life thriller that unfolds like a classic spy story. The heroes here are not dashing secret agents; instead, they are seemingly fanatically dedicated and patient plodders who pore over the myriad possibilities involved in code breaking. Smith shows how the failure to fully understand Japanese cable traffic led to the disaster at Pearl Harbor. He proceeds to illustrate the manner in which Allied cooperation in code breaking led to future successes in the Pacific, including the critical Battle of Midway. This is an engrossing and exciting recounting of an obscure but important facet of World War II. Jay Freeman
Copyright © American Library Association. All rights reserved

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Product Details

• Hardcover: 336 pages
• Publisher: Arcade Publishing; 1St Edition edition (June 11, 2001)
• Language: English
• ISBN-10: 155970568X
• ISBN-13: 978-1559705684
• Product Dimensions: 9.6 x 6.4 x 1.2 inches
• Shipping Weight: 2.3 pounds
• Average Customer Review: 3.1 out of 5 stars  See all reviews (16 customer reviews)
• Amazon Best Sellers Rank: #1,373,377 in Books (See Top 100 in Books)

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Customer Reviews

Most Helpful Customer Reviews

30 of 31 people found the following review helpful:

2.0 out of 5 stars Emperor's Codes - Fails to Decode History, September 1, 2001

By 

Robert McFaul (San Francisco, California) - See all my reviews

This review is from: The Emperor's Codes: The Breaking of Japan's Secret Ciphers (Hardcover)

I recommend buying Emperor's Codes. However, it is just
a small part of the history and has some significant flaws.

Michael Smith's book failed to convince me that the British
were the primary breakers of most Japanese codes and ciphers
before and during the war. Both the British and American invested
increasing resources to identify and break Japanese codes.
The efforts of both were separate, but as the war continued
agreements were worked out to share the results of their
individual work. Some of these efforts were impeded by
politics on both sides. The United States was not the sole
obstructor of efforts to share intelligence. Both sides also
made mistakes in ignoring intelligence from their codebreakers.
Smith's arguments come across as rather one-sided and sound
a bit too resentful for good history in my opinion. He would
have been better off detailing the British and Australian
efforts and let that speak for itself.

He greatly misleads the readers by implying that the breaking
of JN25, the main Japanese Naval Operational Code, by Colonel
Tiltman of GC&CS was a prime British triumph, and that
later codebreaking efforts by Americans to break JN25 was
mere catch up with the British. The fact is JN25A was broken
by Tiltman but not the successor JN25B. JN25B superceeded
JN25A and was a completely new code that was vastly more
complex than JN25A. It was related to JN25A in name only.
The British did not break JN25B. Joe Rochefort and his group

in Hawaii successfully discovered or guessed at enough code
groups to predict the Japanese invasion attempt on Midway, the
greatest code triumph of the war in the Pacific.

One thing I did like about this book was the identification of
the various codes and their purposes. Amongst those id'd
are JN11 (Fleet Auxillary Code), JN40 Naval Shipping Code,
ZMTW or 2468 (Army Shipping Code), JN152 (Navigational Warning
Code), JMA - Coral, etc. So many writers of the Pacific War
refer to the breaking of the 'Japanese Code'. Well, there was
not a single code but many different codes and ciphers with many
different uses. A code as minor as a contact report code used
by the merchant shipping was extremely helpful in identifying
the location of convoys. For this information alone I was happy
to have bought the book.

There is no question that the British and Australians contributed
to the codebreaking efforts in the Pacific. Especially when the
sharing of information enhanced everybody's efforts. For their
efforts I am surely grateful. It saved many lives.

I believe a good history remains to be written that identifies
the various codes, describes the cryptanalysis, the
intelligence value, and how the information was used for each
code. Until that time interested readers must cull through the
various books and piece together the story. I recommend reading
John Prados's 'Combined Fleet Decoded', Edward Drea's
'MacArthur's Ultra', Stripp's 'Codebreakers of the Far East',
and Edwin Layton's 'I Was There'.

40 of 47 people found the following review helpful:

5.0 out of 5 stars Correcting the Cryptographic Record, June 10, 2001

By 

Donald Mitchell "Jesus Loves You!" (Thanks for Providing My Reviews over 109,000 Helpful Votes Globally) - See all my reviews
(VINE VOICE)    (HALL OF FAME REVIEWER)    (TOP 100 REVIEWER)   

This review is from: The Emperor's Codes: The Breaking of Japan's Secret Ciphers (Hardcover)

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 your excellency . . . ." Find enough of those messages, and you could begin to decode.

It was fascinating to see how one source of intelligence helped other parts of the war. The Japanese ambassador in Berlin was a great source of information about Nazi Germany, through the broken Purple code. He toured Normandy just before D-Day, and his rambling account tipped the allies off to the need to throw Hitler's attention towards Pas de Calais.

The book also recounts how a broken message allowed the allies to shoot down Admiral Yamamoto. You also get a very fine explanation of how the coded messages were used to help win the Battle of Midway and the speed the liberation of the Philippines.

Long sections of the story are presented as quoted material from partipants, which provides a change in voice and of perspective. Many of the codebreakers in the various Asian locations were women. What was it like to find a giant snake in the toilet that you so desperately wanted to use? Many of those involved in codebreaking married, and had to deal with the many British retreats (from Hong Kong to Singapore to Colombo to Mombasa). Their stories will make all of this much more appealing and personal to you.

After you finish understanding how valuable it is to understand your opponent, think about your competitors in work or play activities. How well have you undertaken to understand what they are thinking about in order to anticipate what they will do next? For those you serve, don't forget that you can ask them directly.

Get to the bottom of important puzzles!

18 of 22 people found the following review helpful:

4.0 out of 5 stars Good, but with some bias, June 20, 2001

By 

Nathaniel H. Biggs "The History Guy" (Long Valley, NJ) - See all my reviews
(REAL NAME)   

This review is from: The Emperor's Codes: The Breaking of Japan's Secret Ciphers (Hardcover)

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.