Although most Americans knew very little about the American soldiers of Japanese ancestry serving their country, the accomplishments of the 100th Infantry Battalion/442nd Regimental Combat Team were almost legendary among the Allied and US armed forces.

Yet the efforts of a special group of Japanese American soldiers remained largely unknown and purposefully hidden from the public eye until about three decades after the end of World War II. This group was the Military Intelligence Service (MIS).

The MIS servicemen included Nisei and Kibei (Nisei educated in Japan) who were specifically recruited for their linguistic ability. Japan firmly believed that its language was too complex for any foreigner to comprehend. Its leaders therefore thought that their battle plans were perfectly safe from opponents and did not need a special code to remain secret. Japan neglected to consider that some Japanese Americans had learned the language or had been educated in Japan.

The US military brought together these young Nisei and others fluent in the Japanese language to perform combat intelligence and psychological warfare. Trained intensively at the Military Intelligence Service Language School (MISLS), formerly the Fourth Army Intelligence School, the MIS held the important task of translating captured enemy documents, interrogating POWs, creating propaganda, and participating in war crime trials. The men served confidentially, working as individuals or in small units assigned to combat divisions in many of the campaigns in the Pacific after the battle of Midway, the decisive naval battle of June 1942. They served not only with the US Armed Forces, but also with other Allied armed forces, including those of Australia, Canada, China, Great Britain, India, and New Zealand.1

President Harry Truman referred to the MIS as the “human secret weapon for the US Armed Forces.” Major General Charles A. Willoughby, the chief of intelligence for General Douglas MacArthur, reportedly praised the MIS, pronouncing that its work shortened the Pacific war.2 Both Colonel Sydney Mashbir, Allied Translator and Interpreter Section (ATIS) coordinator, and Colonel Kai E. Rasmussen, MISLS commander, concurred, the latter stating also that the Nisei “saved the lives of thousands of American soldiers and billions of American Dollars [sic].”3 The men of the MIS were the “eyes and ears” of the US in the fight against Japan.

The MIS soldiers were shipped out to various locations in the Pacific and Southeast Asia, from Alaska and the Philippines, to Australia and Japan. Their work was important for several battles, such as those in the Philippine Sea, Okinawa, and Bougainville. The MIS was crucial to the capture and translation of the “Z Plan” document that contained Japan’s entire defense strategy and tactical plan for the Marianas Islands and the Philippines. The MIS also served in the China-Burma-India Theater, participating in important combat missions.

Even after the war had ended, the MIS worked tirelessly for the US Armed Forces. Linguists continued their role during the occupation and rebuilding of Japan after the war, becoming the essential link between General Douglas MacArthur’s general headquarters and the Japanese people.

Although subject to distrust throughout the war, the MIS Nisei were eventually recognized as invaluable to every group in the Pacific. Their jobs were often dangerous and made more difficult by their ambivalent position within the armed forces. Like other Americans of Japanese descent, the MIS Nisei were the objects of suspicion and fear. Like other Nisei soldiers, they had to work doubly hard to prove their loyalty as Americans. But perhaps even more so than other Nisei soldiers, the MIS linguists occupied a contradictory space within the war. Within the MIS organization itself, the Nisei were responsible for highly classified information, yet they themselves were constantly subjected to intense scrutiny.4 They were almost always accompanied or led by a Caucasian officer. In all, 6,000 men graduated from MISLS and served in the MIS.5

In 1972, President Richard Nixon signed Executive Order 11652, declassifying all military intelligence documents during World War II. The role of the MIS was finally brought to light as its stories and experiences were revealed to the general public.

In June 2000, the MIS received a well-deserved Presidential Unit Citation, the highest possible military award for a unit in the US Armed Forces.


  • 1Ted Tsukiyama, “The Nisei Intelligence War Against Japan,”, November 19, 2004
  • 2John E. Anderton and Bradford Smith quoted in James C. McNaughton, Nisei Linguists: Japanese Americans in the Military Intelligence Service during World War II (Washington, DC: Department of the Army, 2006), p. 460.
  • 3Ibid.
  • 4See, for example, James C. McNaughton’s discussion of MISLS students at the school itself. McNaughton, Nisei Linguists: Japanese Americans in the Military Intelligence Service during World War II (Washington, DC: US Army Center of Military History, 2006), p. 114.
  • 5“Fort Snelling: Breaking the Code,”, last modified December 23, 2014
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