U.S.-Born Nisei Were a U.S. Secret Weapon : World War II: Graying heroes now, these Japanese-American volunteers share fascinating spy tales of how they helped to shorten the war in the Pacific.

At a time when anti-Japanese sentiment was at its peak during World War II, a small group of Japanese-American volunteers participated in highly secret missions that helped turn the tide in the fight against the land of their ancestors.

Second-generation Japanese-Americans, or Nisei, were taken into the Military Intelligence Service and were considered a secret weapon in the war against Japan.

While historians have chronicled the exploits of another Japanese-American group, the much-honored 442nd Regimental Combat Team, the efforts of those in the MIS, who worked covertly to bring an end to the war in the Pacific Theater, have only recently come to light.

The missions of Japanese-Americans in the MIS were so sensitive that official documents remained sealed until a few years ago.

Few knew that many in the MIS were Americans who looked more like the enemy they happened to be fighting.

Even the War Department was at first leery of using the Nisei because of uncertainty about their loyalties.

But their loyalty and know-how proved to be important factors in the Allies’ triumph in the Pacific Theater.

Beginning with the Battle of Guadalcanal, members of the MIS, working alone or in small teams, participated in every major battle launched against the Japanese--from Alaska’s frozen tundra, to Australia, to tiny Pacific atolls and the dense jungles of Burma.

Their contributions led Gen. Douglas MacArthur to proclaim, “Never in military history did an army know so much about the enemy prior to actual engagement.”

Other Allied leaders were convinced the work of the MIS saved hundreds of thousands of lives and shortened the war.

The MIS volunteers--original members of the 442nd and 100th Infantry Battalion--received no public acclaim. During their service they were cut off from their families and friends, unable to write to explain their duties in the war effort.

The MIS, which totaled nearly 6,000 by war’s end, served as interpreters, translators, spies and intelligence specialists. They intercepted and monitored radio transmissions and communiques, translated captured maps, journals, letters and other documents which often disclosed critical enemy tactics, operations and troop dispositions.

On the battlefront, they interrogated captured Japanese prisoners, served as translators for military officers and even crawled into caves and tunnels to coax enemy soldiers and civilians to surrender without bloodshed.

Eventually their services were deemed so valuable that MIS personnel were attached to all branches of the U.S. military, including the Office of Strategic Services and the Counter-Intelligence Corps, as well as forces from Great Britain, Australia, Canada and China.

Several dozen MIS members recently held the group’s 50th reunion in Hawaii and many of their ultra-secret missions were revealed.

One of the more human stories of war was related by Ralph Yempuku, who was involved in a unique drama which he didn’t learn about until after he had returned to his forward post in China.

It occurred during the Japanese surrender of the Hong Kong garrison to British forces in 1944.

While the official declaration was being signed, Yempuku failed to notice that it was his younger brother, Donald, bedecked in his Japanese officer’s uniform, who was interpreting the ceremonial proceedings to the Japanese commanding general.

“He saw me, but he didn’t dare say a word,” Yempuku said. “We were only about 20 yards apart, but I guess I was too busy watching the ceremony that I didn’t notice the individuals involved.

“I was really disappointed when I found out about my brother after I got back to Kunming (several hundred miles northwest of Hong Kong). I hadn’t seen him in 11 years and, because of the repatriation process, it was another couple of years before we caught up with each other.”

Donald, who had returned to Japan with his parents before the war, explained that he did not attempt to contact his brother because it was a surrender to the British, not the Americans.

He wasn’t sure what the Britons’ reaction would have been had he saluted his brother wearing an American officer’s uniform. Donald Yempuku died last year in Japan.

After the Japanese attack on Pearl Harbor, Yempuku, who held an ROTC commission, and several Japanese-American friends volunteered for the Hawaii Territorial Guard.

They patrolled beaches, guarded utility installations and enforced blackouts throughout Honolulu.

But it wasn’t long thereafter that all the Japanese-Americans were summarily discharged because of the uncertainty about their loyalty.

To show that they could be trusted, however, the Hawaii Nisei formed the Varsity Victory Volunteers.

Yempuku later became one of the first volunteers for the famous 442nd Regimental Combat Team and was sent to Camp Shelby, Miss. It was there that he was tapped for duty with the Office of Strategic Services, which was the forerunner of the Central Intelligence Agency.

The volunteers were taken to Camp Savage, Minn., where they received training in sending and receiving Morse Code and then shipped to a secret base on Santa Catalina Island, off the California coast, for hand-to-hand and unorthodox combat training.

“As we went through the training, I figured we were in for an assignment that would be different,” Yempuku said.

It wasn’t long before Yempuku, given a Chinese-sounding surname while crisscrossing the U.S. mainland, was dropped into North Burma--behind the Japanese lines--and assigned with two other Americans and a British officer to work with the Kachins, a fierce Burmese guerrilla group that hated the Japanese.

After the war, Yempuku set out to find his family by extending his stay for a year with the Counter-Intelligence Corps in Japan.

After a month of searching, he found them living on an island off Hiroshima, which had been devastated by the atomic bomb.

“When they first saw me, they thought they were seeing a ghost,” he said. “They were really shocked to see me because the Japanese propaganda machine said all Nisei had been used as cannon fodder. So they assumed I was dead.”

It was then that he learned two other brothers had been conscripted by the Japanese military. A fourth brother was too young for military duty.

In looking back, Yempuku thinks it might have been a good thing that the Japanese in Hawaii were mistrusted.

“Otherwise, we’d never (have) done what we did,” he said. “We’d still be second-class citizens.”

But 50 years later, the citizenship question remains.

Several months ago, Ted Tsukiyama, an MIS veteran, stood at the National Memorial Cemetery of the Pacific quietly studying the murals of the Pacific war battles.

The reverie of the moment was shattered when a tourist approached and asked, “Which side did you fight on?”

Surrounded by the graves of the dead from four wars, particularly those of his fallen Japanese-American comrades, Tsukiyama said, “That question hurt deeply, right to the core.”