MacArthur's Ultra: Codebreaking and the War Against Japan, 1942-1945 (Modern War Studies) [Paperback]

Edward J. Drea (Author)

Book Description

Publication Date: February 1993 | Series: Modern War Studies

Cracking the enemy's radio code is a task so urgent and so difficult that it demands the military's best minds and most sophisticated technology. But when the coded messages are in a language as complex as Japanese, decoding problems multiply dramatically.

It took the U.S. Army a full two years after the attack on Pearl Harbor to break the codes of the Japanese Imperial Army. But by 1944 the U.S. was decoding more than 20,000 messages a month filled with information about enemy movements, strategy, fortifications, troop strengths, and supply convoys.

In MacArthur's ULTRA, historian Edward Drea recounts the story behind the Army's painstaking decryption operation and its dramatic breakthrough. He demonstrates how ULTRA (intelligence from decrypted Japanese radio communications) shaped MacArthur's operations in New Guinea and the Philippines and its effect on the outcome of World War II.

From sources on both sides of the Pacific and national security agency declassified records, Drea has compiled a detailed listing of the ULTRA intelligence available to MacArthur. By correlating the existing intelligence with MacArthur's operational decisions, Drea shows how MacArthur used--and misused--intelligence information. He tells for the first time the story behind MacArthur's bold leap to Hollandia in 1944 and shows how ULTRA revealed the massive Japanese mobilization for what might have been (had it occurred) the bloodiest and most protracted engagement of the entire war--the Allied invasion of Japan. Drea also clarifies the role of ULTRA in Truman's decision to drop atomic bombs on Japan in 1945, and concludes that ULTRA shortened the war by six to ten months.

This book is part of the Modern War Studies series.

Editorial Reviews

From Publishers Weekly

The acronym "ULTRA," as employed here, refers to special intelligence derived from the interception and decryption of Japanese radio traffic and its use by Gen. Douglas MacArthur in his New Guinea and Philippines campaigns. Drea's excellent study uncovers the motivation behind certain command decisions that have puzzled historians, particularly in regard to the 1944 Hollandia operation in New Guinea. He demonstrates how ULTRA enabled MacArthur to select the weakest point in the enemy's defenses and then strike with overwhelming superiority. On the other hand, Drea also shows that MacArthur's use of ULTRA became a "hit or miss proposition" after Hollandia, and comes to the surprising conclusion that the general did not rely heavily on ULTRA, usually dismissing intelligence that failed to mesh with his preconceived strategic vision. The book presents a detailed illustration of the interplay between intelligence-gathering and operational planning, and uses one of history's most successful commanders as its model. Drea is chief of the research and analysis division at the Army Center of Military History in Washington, D.C. Photos.
Copyright 1991 Reed Business Information, Inc. --This text refers to an out of print or unavailable edition of this title.

From Library Journal

Ten years after the appearance of Ronald Lewin's The American Magic: Codes, Ciphers, and the Defeat of Japan ( LJ 1/1/82), Drea has produced a revisionist view of American strategy and decision-making in the Pacific theater of World War II. Drea posits that MacArthur's access to ULTRA radio intercepts and decoding gave him an enormous advantage over the Japanese, an advantage he did not always employ. The "American Caesar" tended to believe radio intercepts that reinforced his preconceptions of Japanese resources and strategy at the expense of other intelligence. The decision to employ atomic weapons against Japan is presented as based upon analysis of Japanese anti-invasion defenses, and MacArthur's postwar flip-flop--his criticism of the use of atomic weapons--is seen as consistent with his pattern of intelligence use and misuse. This important study belongs in all World War II collections, but readers unfamiliar with events in the Pacific theater might be advised to keep one of the single-volume histories of the war at hand, since Drea is more interested in documenting decision-making than in producing a traditional campaign history. Previewed in "The Day of Infamy in Print," LJ 9/1/91, p. 206-7.-- Stanley Planton, Ohio Univ.
Chillicothe Lib.
Copyright 1991 Reed Business Information, Inc. --This text refers to an out of print or unavailable edition of this title.

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Product Details

• Paperback: 312 pages
• Publisher: University Press of Kansas (February 1993)
• Language: English
• ISBN-10: 0700605762
• ISBN-13: 978-0700605767
• Product Dimensions: 9 x 6 x 0.9 inches
• Shipping Weight: 15.2 ounces (View shipping rates and policies)
• Average Customer Review: 4.0 out of 5 stars  See all reviews (1 customer review)
• Amazon Best Sellers Rank: #1,313,261 in Books (See Top 100 in Books)

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1 of 1 people found the following review helpful:

4.0 out of 5 stars New light on a fascinating topic, April 1, 2011

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This review is from: MacArthur's Ultra: Codebreaking and the War Against Japan, 1942-1945 (Modern War Studies) (Paperback)

US Army/Navy codebreaking (Magic program) has been well covered in previous histories. Macarthus's Ultra covers a topic that has been rather neglected until now. Perhaps more detail than some might prefer, and could use more maps to illustrate various shifts in strategic direction, but altogether a very satisfying effort. Well worth the modest price.