This book reveals the historical context and the evolution of the technically complex Allied Signals Intelligence (Sigint) activity against Japan from 1920 to 1945. It traces the all-important genesis and development of the cryptanalytic techniques used to break the main Japanese Navy code (JN-25) and the Japanese Army’s Water Transport Code during WWII. This is the first book to describe, explain and analyze the code breaking techniques developed and used to provide this intelligence, thus closing the sole remaining gap in the published accounts of the Pacific War. The authors also explore the organization of cryptographic teams and issues of security, censorship, and leaks. Correcting gaps in previous research, this book illustrates how Sigint remained crucial to Allied planning throughout the war. It helped direct the advance to the Philippines from New Guinea, the sea battles and the submarine onslaught on merchant shipping. Written by well-known authorities on the history of cryptography and mathematics, Code Breaking in the Pacific is designed for cryptologists, mathematicians and researchers working in communications security. Advanced-level students interested in cryptology, the history of the Pacific War, mathematics or the history of computing will also find this book a valuable resource.

Fortunately for the Americans in the Pacific, the Japanese sincerely believed that it was not possible for Westerners to learn their language. Lulled by this misapprehension into a false sense of security, they could only ascribe to luck or coincidence the remarkable frequency with which the Americans intercepted their plans.

Elliot Carlson’s award-winning biography of Capt. Joe Rochefort is the first to be written about the officer who headed Station Hypo, the U.S. Navy’s signals monitoring and cryptographic intelligence unit at Pearl Harbor, and who broke the Japanese navy’s code before the Battle of Midway. The book brings Rochefort to life as the irreverent, fiercely independent, and consequential officer that he was. Readers share his frustrations as he searches in vain for Yamamoto’s fleet prior to the Japanese attack on Pearl Harbor, but share his joy when he succeeds in tracking the fleet in early 1942 and breaks the code that leads Rochefort to believe Yamamoto’s invasion target is Midway. His conclusions, bitterly opposed by some top Navy brass, are credited with making the U.S. victory possible and helping to change the course of the war. The author tells the story of how opponents in Washington forced Rochefort’s removal from Station Hypo and denied him the Distinguished Service Medal recommended by Admiral Nimitz. In capturing the interplay of policy and personality and the role played by politics at the highest levels of the Navy, Carlson reveals a side of the intelligence community seldom seen by outsiders. For a full understanding of the man, Carlson examines Rochefort’s love-hate relationship with cryptanalysis, his adventure-filled years in the 1930s as the right-hand man to the Commander in Chief of the U.S. Fleet, and his return to codebreaking in mid-1941 as the officer in charge of Station Hypo. He traces Rochefort’s career from his enlistment in 1918 to his posting in Washington as head of the Navy’s codebreaking desk at age twenty-five, and beyond. In many ways a reinterpretation of Rochefort, the book makes clear the key role his codebreaking played in the outcome of Midway and the legacy he left of reporting actionable intelligence directly to the fleet. An epilogue describes efforts waged by Rochefort’s colleagues to obtain the medal denied him in 1942—a drive that finally paid off in 1986 when the medal was awarded posthumously.

The award-winning New York Times bestseller about the American women who secretly served as codebreakers during World War II--a "prodigiously researched and engrossing" (New York Times) book that "shines a light on a hidden chapter of American history" (Denver Post). Recruited by the U.S. Army and Navy from small towns and elite colleges, more than ten thousand women served as codebreakers during World War II. While their brothers and boyfriends took up arms, these women moved to Washington and learned the meticulous work of code-breaking. Their efforts shortened the war, saved countless lives, and gave them access to careers previously denied to them. A strict vow of secrecy nearly erased their efforts from history; now, through dazzling research and interviews with surviving code girls, bestselling author Liza Mundy brings to life this riveting and vital story of American courage, service, and scientific accomplishment.

The extraordinary untold story of the brilliant men who cracked the Japanese codes from Australia during World War II. At the height of World War II in the Pacific, two secret organisations existed in Australia to break Japan's military codes. They were peopled by brilliant and idiosyncratic cryptographers, including some with achievements in mathematics and the Classics and others who had lived or grown up in Japan. These men patiently and carefully unravelled the codes in Japanese signals, ultimately playing a crucial role in the battles of Midway and the Coral Sea, as well as Macarthur's push into the Philippines. An intercept station in the Queensland bush brought about the end of Admiral Yamamoto. But this is more than a story of codes. It is an extraordinary exploration of a unique group of men and their intense personal rivalries and loathing, of white-anting and taking credit for others' achievements. It is also the story of a fierce inter-national and inter-service political battle for control of war-changing intelligence between a group of cryptographers based at the Monterey apartment block in Melbourne's Albert Park and General MacArthur's counter group that eventually established its headquarters in suburban Brisbane. What happened between these two groups would have consequences for intelligence services in the years to follow. Code Breakers brings this surprising and very secret world and the men who operated in it to rich life for the first time.

This book reveals the historical context and the evolution of the technically complex Allied Signals Intelligence (Sigint) activity against Japan from 1920 to 1945. It traces the all-important genesis and development of the cryptanalytic techniques used to break the main Japanese Navy code (JN-25) and the Japanese Army’s Water Transport Code during WWII. This is the first book to describe, explain and analyze the code breaking techniques developed and used to provide this intelligence, thus closing the sole remaining gap in the published accounts of the Pacific War. The authors also explore the organization of cryptographic teams and issues of security, censorship, and leaks. Correcting gaps in previous research, this book illustrates how Sigint remained crucial to Allied planning throughout the war. It helped direct the advance to the Philippines from New Guinea, the sea battles and the submarine onslaught on merchant shipping. Written by well-known authorities on the history of cryptography and mathematics, Code Breaking in the Pacific is designed for cryptologists, mathematicians and researchers working in communications security. Advanced-level students interested in cryptology, the history of the Pacific War, mathematics or the history of computing will also find this book a valuable resource.

Central Bureau - Australia's own large and sophisticated intelligence network, built from scratch. It was this group of mathematicians, code-breakers, and radio experts who intercepted the travel plans of the architect of the Pearl Harbor attack, Admiral Yamamoto, leading to his ambush and death. Australian signals intelligence also played a vital role in the battles of the Coral Sea, Milne Bay, Hollandia, and many others. General Douglas MacArthur, the supreme commander of the local Allied forces, went so far as to insist that the men of Central Bureau accompany him on his counter-attack in the Pacific. After the war, the US sought to give these non-combatants the highest awards possible - honours that were suppressed by the Australian government in their need for secrecy. A groundbreaking work of military history, The Secret Code-breakers of Central Bureau gives these talented and dedicated individuals their due at last. It is a rich account of the shadowy side of military strength and of the men and women whose work was, in the words of the US navy, of 'immeasurable importance in the successfulmprosecution' of the Pacific War. 'Who knew? This enthralling study tells a deeply human story. The men and women who gave our troops a significant edge in the fight against the Japanese are the genuine heroes in this engaging and exciting book.' -Michael McKernan, author of The Strength of a Nation and When This Thing Happened 'This is history and military strategy written at its most engaging.' -Waikato Times 'A delightfully and thoroughly engaging story of the emergence of the Australian contribution to the signals and radio interception intelligence ... Dufty's writing style is light and easy to read, reminiscent of other contemporary historical narratives that tell a series of stories, most notably the emphasis of the human story associated with these experiences.' -Rhys Ball, NZ International Review

This book is about Americans not of Japanese ancestry, who served as Japanese language officers in World War II. Covering the period 1940-1945, it describes their selection, training, and service in the Navy and Marine Corps during the war and their contributions to maintenance of good relations between America and Japan thereafter. It argues that their service as “code breakers” and combat interpreters hastened victory and that their cross-cultural experience and linguistic knowledge facilitated the successful dismantling of the Japanese Empire and the peaceful occupation of Japan. The book shows how the war changed relations between the Navy and academia, transformed the lives of these 1200 men and women, and set onetime enemies on course to enduring friendship. Its purpose is twofold: to reveal an exciting and hitherto unknown aspect of the Pacific War and to demonstrate the enduring importance of linguistic and cross-cultural knowledge within America’s armed forces in war and peace alike.The book is meant for the general reader interested in World War II, as well as academic specialists and other persons particularly interested in that conflict. It will also appeal to readers with an interest in America’s intelligence establishment and to those interested in Japan and its relations with the United States. This history tells and exciting and previously unknown story of men and women whose brains and devotion to duty enabled them to learn an extraordinarily difficult language and use it in combat and ashore to hasten Japan’s defeat and transformation from enemy to friend of America.

During the Second World War, Australia maintained a super-secret organisation, the Diplomatic (or `D’) Special Section, dedicated to breaking Japanese diplomatic codes. The Section has remained officially secret as successive Australian Governments have consistently refused to admit that Australia ever intercepted diplomatic communications, even in war-time. This book recounts the history of the Special Section and describes its code-breaking activities. It was a small but very select organisation, whose `technical’ members came from the worlds of Classics and Mathematics. It concentrated on lower-grade Japanese diplomatic codes and cyphers, such as J-19 (FUJI), LA and GEAM. However, towards the end of the war it also worked on some Soviet messages, evidently contributing to the effort to track down intelligence leakages from Australia to the Soviet Union.

In the foreword to this book, first published in 1978, Sen. Daniel Inouye describes the story as ""the raw material of adventure fiction--but this is all true and told in a manner that is at the same time fascinating and professional."" Despite the passage of twenty years and the appearance of several studies of code breaking, this inside look at naval intelligence in the Pacific is as powerful as ever. This book provides a compassionate and unique understanding of the war and the business of intelligence gathering. Assigned to the combat intelligence unit in Honolulu from June 1941 to the end of the war, W. J. Holmes shares his history-making experiences as part of an organization that collected, analyzed, and disseminated naval intelligence throughout World War II. His book not only captures the mood of the period but gives rare insight into the problems and personalities involved, allowing the reader to fully appreciate the painful moral dilemma faced daily by commanders in the Pacific once the Japanese naval codes were broken. Every time the Americans made use of the enemy messages they had decoded, they increased the probability of the Japanese realizing what had happened and changing their codes. And such a change would cause the U.S. Pacific Fleet to lose a vital edge. On the other hand, withholding the information could--and sometimes did--result in the loss of U.S. lives and ships. This revealing study illuminates the difficulties in both collecting intelligence and deciding when to use it.