The Japanese-American U.S. Army Intelligence Unit that helped win WWII

The Defense Language Institute Foreign Language Center in Monterey, California, traces its roots to the secret World War II U.S. Army intelligence unit comprised of Japanese-Americans – the Military Intelligence Service (MIS). 

Then, as now, we needed to succeed militarily and also communicate with other cultures and nations. 

The MIS was started in late 1941 as a unit to train Japanese-Americans (Nisei) to conduct translation and interrogation activities. MIS men came mostly from Hawaii and the West Coast.

The missions of the MIS were highly classified and still are not widely known. Much information about MIS activities remained classified until 1972 when President Richard Nixon signed Executive Order 11652 making certain WWII intelligence documents eligible for declassification. 

After the Pearl Harbor attack, the people of the United States found themselves in a war with the military of a culture quite different from our own: Japan. The Japanese military and Japanese society had, in many ways, a different social fabric, a different psychology, different spiritual traditions and was a different ethnic group in significant ways.


After Pearl Harbor, first- and second-generation Japanese-Americans in Hawaii and California faced tough scrutiny by our defense and national security community. Were there spies and saboteurs among them? Were they loyal to America or Japan, or torn between the two? 

In California, in part due to racial prejudice and hate-mongering, patriotic Japanese-American farmers, merchants, professionals and their families were forced into harsh detention camps in remote regions of the West for the duration of the war. 

In Hawaii, where Japanese-Americans were well-integrated into the community, there reportedly were fewer attempts to randomly suspect or imprison them. Nisei living in Hawaii generally did not experience the extreme measures faced by those on the West Coast.

Meanwhile, many young men from these families and communities joined the U.S. military, in part to prove their patriotism. Many ended up in the MIS as well as the famed and highly-decorated U.S. Army 442nd Regimental Combat Team and the 100th Infantry Battalion, fighting in Italy and elsewhere in Europe. 

They did all this while many of their family members were behind barbed-wire fences in detention camps back in the U.S. 

Young Japanese-American men joined the military for many reasons including proving their loyalty to the United States and proving that they were good Americans. Many had been raised as somewhat typical American kids.


The MIS organization included an administrative group, an intelligence group, a counterintelligence group and an operations group. The MIS performed a very wide range of important and often dangerous activities.  

As American and allied forces move into the Pacific theater to engage the Japanese navy and army,  MIS men were on the tip of the spear, attached to U.S. Navy, Army and Marine units as well as the joint Australian-American "Allied Translator and Interpreter Service." MIS members served with "Merrill's Marauders," the famous Army Ranger unit that conducted operations in Burma against the Imperial Japanese Army. 

MIS personnel were active in nearly all major campaigns and battles in the Pacific as well as in Burma and China. 

According to some assessments, MIS missions may have shortened the Pacific war by up to two years.

They performed intelligence and counterintelligence tasks such as intercepting radio messages, interrogating prisoners, translating captured maps and documents, helping in psychological and information operations efforts, infiltrating enemy lines and flushing caves - convincing civilians and Japanese soldiers to leave caves on remote islands, and persuading many Japanese troops to surrender. 

MIS interrogators reportedly used psychological and cultural understanding to obtain valuable intelligence. Interestingly, MIS men reportedly provided decent treatment for Japanese prisoners and obtained information by building rapport with captured Japanese troops.

After the war, more than 5,000 MIS personnel worked in Japan during the occupation by the U.S. from 1945 to 1952. They were assigned to the occupation military government in disarmament, intelligence, civil affairs, finance, education and land reform. The MIS also helped develop the Japanese constitution.


The United States fought a long military struggle in the Pacific. Then, we occupied Japan with the goal of rebuilding and rehabilitating that society by implementing a peaceful democracy. Both of these efforts were successful. 

Men of the MIS also demonstrated intelligence and compassion both during the war and in the occupation. They helped win a military victory, then helped make peace and win friends for the United States. 

They were key in rebuilding the nation of Japan and helping that society recover from devastating social, psychological and physical damage. 

In examining the MIS, we must also ask why did these Japanese-American young men, mostly from the west coast and Hawaii, join the MIS (and the 442nd RCT and 100th Infantry Battalion)? Why did they side with America against the military of the land of their parents, grandparents and ancestors? 

Although most were raised as American kids, they experienced significant racial prejudice and discriminatory laws. After Pearl Harbor, Japanese American families had been stripped of property and businesses and forced into the infamous relocation camps. MIS men emerged out of this environment. 

Now may be the time to review the activities of the MIS and apply lessons learned. These WWII veterans are now up in years and many have passed on. 

Our special operations forces and intelligence personnel would be wise to consult these MIS vets whose language and human skills were so crucial in WWII. How did the MIS conduct their intelligence and rapport-building operations? What can MIS vets teach us? 

As we deal with global issues today, information about the MIS may provide useful perspectives.

For more information: 

Review of a book about the MIS available on the Central Intelligence Agency website: “Nisei Linguists: Japanese Americans in the Military Intelligence Service During World War II:”… 

Go For Broke National Education Center website: