In an overlooked and underrated chapter of World War II, thousands of second-generation Japanese-Americans, or nisei, came to Minnesota for military language training as the war intensified.

After accelerated linguistic cram courses in Savage and then at Fort Snelling, graduates of the Military Intelligence Service Language School were shipped overseas in small teams to every stage of the Pacific theater — from Burma to Okinawa.

They translated captured documents, interpreted enemy orders, interrogated prisoners, monitored radio messages and wrote propaganda aimed at convincing Japanese soldiers and civilians to surrender.

"The Nisei shortened the Pacific War by two years," said Gen. Charles Willoughby, chief of military intelligence for Gen. Douglas MacArthur, "and saved possibly a million American lives and saved probably billions of dollars."

Their exploits were classified and kept a military secret for 50 years. That's one reason why, as the world commemorates the 70th anniversary of the war's end, "most Minnesotans know nothing about the language school," said Sally Sudo, of Bloomington.

She's a co-chair of the Twin Cities chapter of the Japanese American Citizens League — and one of a handful of local women trying to raise awareness of the critical role that the Minnesota language schools played. Together with the Minnesota Historical Society, the group is sponsoring a display of rare World War II photographs at the Fort Snelling Visitors Center opening May 17.

Nisei scholars trained at the Military Intelligence Service Language School at Fort Snelling during World War II.

For Sudo, it's personal. Her late brother, Joe E. Ohno, was one of the 6,000 nisei soldiers to go through the school. He volunteered at 18, the day after graduating from an Idaho high school in 1943. The rest of the family were forced from their home in Seattle and confined, along with more than 120,000 people of Japanese ancestry. Two-thirds of those interned under President Franklin Roosevelt's order were U.S. citizens.

Ohno served in the Philippines and then Occupied Japan with the Ministry of Finance. After the war, he went to the University of Minnesota on the G.I. Bill and earned a math degree. He worked for the New Orleans Police Department, where he set up its computer system. He died in 2002 at age 76.

While much of the nation suspected that Japanese-Americans were disloyal and up to no good after Pearl Harbor, Minnesota was different — thanks to Gov. Harold Stassen and a young bureaucrat named Hubert Humphrey who, in his early 30s, was named the state's War Service Program director.

The military language school opened in an abandoned hangar in San Francisco's Presidio in November 1941 — just a month before Pearl Harbor was attacked.

The War Department saw a conflict looming and scrambled to get soldiers familiar with Japanese. Japan's military leaders were privately boasting that their communications were safe from Westerners because few spoke their language — and even fewer could decode a Japanese shorthand and a dialect used for military affairs.

"The nisei linguists were among the few Americans who could speak, read and write the complex Japanese language," said Janet Carlson, a retired Macalester College chemistry professor and Japanese American Citizens League leader. "There was not one case of espionage or sabotage ever identified among Japanese-Americans in World War II."

After the U.S. military was rocked by the sneak attack on Pearl Harbor, Roosevelt's Executive Order 9066 forced the removal of all people of Japanese ancestry from California and parts of Oregon, Washington, Arizona and the Alaska Territory.

That forced the language school to move.

"Stassen assured everyone in the military that Minnesota would be a good place to be for this language program," said Carolyn Nayematsu, another league member, during a group interview at her Summit Avenue home in St. Paul.

Stassen offered up Camp Savage, a former Works Progress Administration camp and later a home for the poor. The initial class of 200 students and 18 instructors convened on June 1, 1942. By August 1944, the program had outgrown its facilities and moved to nearby Fort Snelling through 1946.

Although most of those trained at Fort Snelling were men, in November 1944, nearly 50 nisei members of the Women's Army Corps studied the same curriculum and became written language translators.

After the war, graduates of the language school translated and worked as interpreters at war crimes tribunals and served myriad roles in the occupation of Japan.

"Bridging the language and cultural barriers between Japan and the United States, they played a pivotal role in one of the most constructive and historic occupations in the history of the world, and laid the groundwork for the creation of a valuable, stable, peacetime ally," Carlson said.

Many of the Minnesota-trained nisei soldiers decided to stay put. The 1940 census shows 51 people of Japanese heritage in Minnesota — mostly railroad workers. By 1950, that number had grown more than 20-fold to 1,049.

Curt Brown's tale on Minnesota's history appears each Sunday. Readers can send him ideas and suggestions at mnhistory@startribune.com