Figure 1.--

Japan beginning with the first Sino-Japanese War (1894-95) engaged in a series of scuccessful wars which built an empire in east Asia. They event humiliated Russia (1904-05). The role of the inteligence services is rarely discussed in historical accounts. The role of intelligence in World War II is much more widely discussed, but usually from the Allied side. The Japanese collected information on Pearl Harbor before the War. The resulting attack (Decembr 1941)which is usually depicted as amajor success. In fact it was a cataclysmic intelligence failure. The goal of the attack was to destroy the American Pacific Fleet's carriers. In fact not one was present. The Japanse did sink the eight battleships they found at Pearl, but sestroyed only three. And as the Pacific War would later show, these battleships were largely obsolete. And in exchange for this phyric victory, Japan found itself at war with the United States. Their major intelligence success occurred early in the War, obtaining information on the defenses of Singapore. The fall of the British bastion was one of the great shocks of the War (April 1942). After Singapore, however, Japanese intelligence played little role in the War. And the Ichi-Go offensive in China was based on information they acquired about the planned strategic bombing campaign. The results, however, were negated when the Americans seized the Mariana Islands in the Central Pacific (June 1944). It was the American intelligence services that played a major role in the War, breaking the Japanese naval codes. Even after the Coral Sea (April 1942), thecJapanese intelligence services failed to conclude that the naval codes had been broken. This made possible the American victory at Midway (June 1942), a vicyory from whih the Japnese Navy never recovered. Throught the War, the inteligence services were never able to correctly assess the status of American naval forces. The critical inteligence information in the Pacific War would prove to be codes.

Historical Background

Japan beginning with the first Sino-Japanese War (1894-95) engaged in a series of scuccessful wars which built an empire in east Asia. They event humiliated Russia (1904-05). The role of the inteligence services is rarely discussed in historical accounts. [Kotani]

American Pre-World War II Code Breaking

One of the great figures in American cryptolgy is Herbert O. Yardley. He was the director of Military Intelligence's cryptanalytic service MI_8 during World War I. Their primary objective was to break German codes. Most of the U.S. Army after World War was stood down. Yardley's operation was, however, continued. He set up shop in New York where he operated his code-breaking operation under a commercial cover. It was the famed "American Black Chamber". Rather than the Army, it was funded by both the Departments of State and Navy. After the War, America's most pressing foreign policy problem was Japan and the growth of Japanese naval power. The Harding Administration convened the Washington Naval Arms Limitation Conference (1921-22). The Black Chamber succeeded in breaking the Japanese diplomatic code. American diplomats used the decripts at the Conference. This was unknown to the Japanese. Republican President Hoover appointed Henry Stimson Secretary of State (1929). In a great irony of history, Stimson closed down the Black Chamber with the dismissive comment, "Gentlemen don't read other gentlemen's mail." Democratic President Roosevelt would later bring Stimson into his cabinent as Secretary of War to create a bipartisan consensus on war issues (1940). And it would be Sectrtary Stimson after pouring over decrypts of Japanse diplomatic messages that would recieve Japanese envoys after the attack on Pearl Harbor (1941). While Stimson had ended State Department funding and effectively closed down Yardley's Black Chamber, he did not stop American code breaking which is why as Secretary of War he was reading decoded Japanese diplomatic messages. The US Army took over the Black Chamber files and established its own code-breaking group, the Signals Intelligence Service directed by William Friedman. The U.S. Navy had previously established a Code and Signal Section within the Office of Naval Intelligence (1924). Both services focused on breaking Japanese codes. The Japanese had no idea theor codes had been broken. The secret was never uncovered by the Japanese coubter-intelligence services. Rather the Americans announced what they had done. The unemployed Yardley published The American Black Chamber. As a result, the Japanese changed their entire code and cipher system, closing off access to the Americans for several years. The developed a cipher machine similar to the German Enigma Machine which the Foreign Ministry used. The American code breakers referred to as Red. which the Foreign Ministry used. Subsequently they introduced a more advanced machine which the Americans called called Purple (1937). The Foreign Ministry Japanese considered it unbreakable and used it for their most sensitive communications. The Japanese after considerable consideration decided that the best way to take advantage of the war in Europe was to strike south and expand their Empire into Southeast Asia (Late 1939). A few months later, the United States broke into Purple. Thus key American officials were aware of precisely what Japan was doing. Purple was the diplomatic code, not the baval codes that the code (JN-25) that the code brea]kers were also trying to crack. The Purple decrypts in addition to diplomatic matters, however, did include information on intelligence activities and collection targets. The American progrm to decrypt Japanese codes also include work on naval codes and came to be called Magic. Again Japanese countrr-intelligence did not uncover Magic. The Germans learned that the United States were reading Japanese diplomatic messages and informed the Japanese (April 1941). It is not known how the Germans learned of this which was one of the most closely guarded American secrets of World War II.

Japanese Inteligence Gathering in the Americas Before Pearl Harbor

Japanese athorities invaded China (1937) and their military was largely engaged there. While they achieved great victories, the Chinese withdrew to remote areas of the country where the Japanese could not bring their superior military forces to bear. The result was a costly war that Japan could not successfully comclude and refused for reasons of pride, refused to end. America, Britain and France were sympathetic to Chiina, especially when reports of Japanese attrocities surfaced. Western aid delivered through Burma and Indochina (Vietnam) helped keep China in the War to the emense displeasure of the Japanese. When war broke out in Europe, Japanese officials frustrated with the intermenable war in China, considered how to best take advantage of the situation. There were elements that wanted to strike north t the Siviet Union. Others wanted to strike south and seize the needed oil resources of the Dutch East Indies and other resources of Southeast Asia. The Japanese policy debate ended in the victory of the Strike South faction (1939). With the decesion taken, the principal impediment became the American Pacific fleet which President Roosevelt moved forward to Pearl Harbor (1940). The Japanese launched a major effort to obrain intelligence information. The primary target was the United States, but they also wanted information on Latin America for a coming Pacific war. The Japanese during the 1930s had pursued a "cultural enlightenment" approach in the United States. The attroicities committed by the Japanese Army in China, however, had thoroughly blackened the image of Japan in America that no cultural whitewashing could undo. They decided with the victory of the Strike South Faction to pursue a more political course. Interestingly they began to focus on American Communist Party operations and Communist partoes in South America. While the Japanese had ruthlessy suppressed Coomunists in Japan itself, the NAZI-Soviet Non-Aggression Pact (1939) had dramatically affected the outlook of Communist parties around the world. They were ordered to stop opposing Anti-NAZI groups and to oppose efforts to strengthen national defenses. This of course was just what the Japanese wanted. The Japanese espionage agents were ordered to develop details on American relations bwith the Latin American republics. Japan at the time had very limited relations with Latin American countries. The Japanese desired to expand contacts with German and Italian agents who for racial reasons were less conspicuous. They also wanted to use Japanese residents. The Japanese residents they contacted were, however, warnef to be cautious and not to arouse suspion. When Ambassador Nomura arrived in Washington (1940), authorities in Tokyo transmitted revised instructions concerning the gathering of intelligence in both Canada and the United States. American officials thanks to Magic knew that a substantial Japanese espionage organization was functioning in the United States.

The Pacific War (1941-45)

The role of intelligence in World War II is widely discussed by historians, but usually from the Allied side. The Japanese collected information on Pearl Harbor before the War. The resulting Pearl Harbor attack (Decembr 1941) which is usually depicted as amajor success. In fact it was a cataclysmic intelligence failure. The goal of the attack was to destroy the American Pacific Fleet's carriers. In fact not one was present. The Japanse did sink the eight battleships they found at Pearl, but destroyed only two (Arizona and Oklahoma). And as the Pacific War would later show, these battleships were largely obsolete. And in exchange for this phyric victory, Japan found itself locked in a life and death struggle with the United States. Their major intelligence success occurred early in the War, obtaining information on the defenses of Singapore. The fall of the British bastion was one of the great shocks of the War (April 1942). After Singapore, however, Japanese intelligence played little role in the War. And the Ichi-Go offensive in China was based on information they acquired about the planned strategic bombing campaign. The results, however, were negated when the Americans seized the Mariana Islands in the Central Pacific (June 1944). It was the American intelligence services that played a major role in the War, breaking the Japanese naval code--JN-25. Even after the Coral Sea (May 1942), the Japanese intelligence services failed to conclude that the naval codes had been broken. This made possible the American victory at Midway (June 1942), a vicyory from whih the Japnese Navy never recovered. Throught the War, the inteligence services were never able to correctly assess the status of American naval forces. The critical inteligence information in the Pacific War would prove to be codes.

Sources

Kotani, Ken. Japanese Intelligence in World War II (Osprey, 2009).

Yardley, Herbert O. The American Black Chamber.

Created: 1:53 AM 5/2/2009
Last updated: 1:53 AM 5/2/2009