Lee Hak Rae was stunned on March 20, 1947, when he stood in an Australian military court in Singapore and was sentenced to hang as a war criminal for the brutal treatment he was accused of inflicting on ailing Allied prisoners of war who were forced to build the infamous Death Railway to their last breath.

Lee had been specifically accused by nine ex-POWs of collaborating with the Japanese military in forcing sick prisoners to build the Thai-Burma railway until many died.

Lee had been a civilian worker recruited by the Imperial Japanese Army in Korea, which from 1910 to 1945 was under Japanese colonial rule.

"I had never expected to receive the death penalty. I couldn't understand what happened to me," Lee, 82, and now a South Korean resident of Japan, recalled. "When I was handcuffed and felt the metal's coldness, the reality sank in."

Spending eight months on death row in P Hall of Singapore's Changi Prison, Class-B/C war criminal Lee saw other war criminals hanged, including more than 10 Japanese and one Korean.

But then on Nov. 7, 1947, he was summoned by an Australian officer and told his sentence had been commuted to 20 years of hard labor.

The guilty verdict changed Lee's fate. After serving nine years as a war criminal — four years in the Singapore prison and another five years in Tokyo's Sugamo Prison — he devoted his life to supporting other Korean convicted war criminals and their families in their struggle to win an apology and redress from Japan.

During the war, Japan drafted about 240,000 Koreans to serve as "Japanese" soldiers or as civilian workers.

Of these Korean recruits, 148 were convicted as Class-B/C war criminals for war crimes and for abusing POWs, and 23 were hanged, according to research by Aiko Utsumi, a professor at Keisen University in Tokyo and an expert on Koreans convicted of war crimes at the International Military Tribunal for the Far East.

The government excluded Korean war criminals and their families from most of the financial support Japanese war criminals and their families were entitled to, due to their nationality.

When Japan signed the 1952 San Francisco Peace Treaty, restoring its sovereignty, Koreans were stripped of the Japanese citizenship they had been forced to adopt during Japan's colonial rule.

"Japan forced Koreans to participate in the war (as Japanese) but then refused to pay us compensation because (we were suddenly no longer Japanese citizens). That's irrational," said Lee, who now runs a taxi company in Tokyo. "The government's attitude is unforgivable."

Lee lived in a southwestern Korean province until 1942, when, at age 17, he and some 3,000 other Koreans were recruited as civilians to guard Allied POWs in Southeast Asia as the prisoners were forced to build airstrips and railways for the Imperial army.

After two months of basic training at Busan, he was sent to Hintok, Thailand, and, with six other Koreans, guarded some 500 Australian, British and Dutch POWs constructing the 415-km Thai-Burma railway, which was made famous with the movie "The Bridge on the River Kwai."

Lee had to obey Japanese officers eager to build the railway as quickly as possible, and supply them with enough POWs for the construction. But most of the POWs were in a weakened state, many extremely sick, and thus not up to the task, putting the Korean guards in a dilemma, Lee said.

"We didn't know anything about human rights or the Geneva Conventions" stipulating the humane treatment of POWs, he claimed. "We didn't have the power (to resist the Japanese officers)."

The POWs' quarters were makeshift, rough and leaky. They were given little food, clothing or medicine, and many suffered malnutrition and debilitating diseases, including malaria, dysentery and cholera, Lee said, adding many of them died.

It is estimated that more than 10,000 POWs and tens of thousands of Asian laborers died building what became known as the Death Railway.

In 1991, Lee flew to Australia to attend a symposium on the war and meet up with one of the Australian POWs he once guarded in Thailand. The ex-prisoner didn't know Lee had been sentenced to hang for abusing POWs.

"I was still obsessed with the death sentence and my fellow countryman's execution (as a war criminal), so it wasn't easy for me to meet him. But I apologized to him as one of his abusers . . . we understood each other and reconciled," Lee said. "Looking back, I now think I did the right thing (in making the trip)."

After the war ended on Aug. 15, 1945, Lee witnessed the execution of a fellow Korean war criminal. This instilled in him his desire to later help those who were spared.

When Japan surrendered, Lee thought he would finally be able to return to Korea. But he was soon arrested by the Allied forces for the deadly abuse of POWs, and subsequently sentenced to hang.

Lee remembers the last dinners held for his fellow condemned war criminals in Changi Prison's P Hall in 1947, before they were hanged.

They were served rice, miso soup and tempura. Although they were not allowed to drink, they talked about their loved ones, sang songs and danced for two hours.

The one Korean wished his fellow inmates all the best the next morning, and cried out "Independence banzai!" as he was hanged, Lee recalled.

"I was convicted of forcing sick POWs to work. But I just followed Japan's policy on the treatment of POWs," he said. "Some of my fellow countrymen were executed (as war criminals). My mission is to settle the score (with the Japanese government) for the deceased."

Lee was moved from Singapore to Sugamo Prison in 1951 and freed in 1956, but his ordeal, as that of other Koreans convicted of war crimes, continued.

They could not return to what had become South Korea not only because they were on probation, but also because those Koreans who served the Japanese military were branded as collaborators back home, Lee said, noting this stigma forced them to stay in Japan, where they meanwhile had to endure strong discrimination.

"We had no acquaintances (in Japan). There was no place to go and no jobs were available. We were in severe distress," he said, noting the conditions made two of his fellow ex-convicts commit suicide and another two to suffer mental illness.

To change the situation, Lee formed the group Doshinkai in 1955 with 70 other South Koreans with similar experiences.

While demanding that the government equally support Koreans who had been convicted of war crimes and their families, the group set up a taxi company in Tokyo in 1960 to provide members with jobs and a guaranteed livelihood.

In 1991, the group sued the government, demanding an apology and redress. However, the Supreme Court rejected their claim, although it admitted the state failed to enact laws to help the plaintiffs.

Lee said the ruling shows the government has not looked squarely at the fact that Japan caused tremendous damage to many people during the war.

"I will continue our activities until the government shows sincere remorse. This problem will not end even after all of us die," Lee said. "Our following generation will keep raising this issue."

Read more articles in the series Witness to War.