When the son of a captured Dutch soldier, who had been detained in a Japanese labor camp during World War II, learned about the local schoolgirl who, through her piano, helped ease his father's pain, it was almost "too emotional" to bear.

For Robert Stenvert's father, who died in 1992, and the other Allied prisoners of war at a camp in Yokohama, the Japanese teenager's piano practice from her nearby home was more than music to their ears -- it gave the men hope to survive the brutal conditions at the camp, one of many around Japan.

In early November, Robert, 74, who currently lives in Australia, and his wife Edith, 70, visited the Toshiba Tsurumi factory site where his father Theodorus labored for almost a year. He said his father, possibly wishing to shut out "terrible" memories, never told him much about that period of his life.

Taeko Sasamoto, co-chair of POW Research Network Japan, and others led the Stenverts' tour of the site. Sasamoto, 76, and her colleagues researched the actual conditions of facilities in various parts of Japan, compiling them into the nearly 1,000-page "encyclopedia of POW camps and civilian internment camps," which was published last year.

Sasamoto took on the role of guide after being introduced to the couple by her acquaintance while they were vacationing in Japan.

According to the POW network, Dutch soldiers were captured in Indonesia and engaged in labor for the construction of the Thai-Burma Railway linking Thailand and Myanmar, which was being built by the Japanese military.

Also known as "Death Railway," the 415-kilometer track was built through thick jungle and rough terrain to supply Japanese troops in Burma by bypassing sea routes that were vulnerable after the Japanese Navy's significant losses in two pivotal battles. It is estimated that more than 90,000 civilians died building it, as did some 12,000 Allied soldiers.

After arriving in Japan by ship in September 1944, the captured Dutch soldiers endured cruel working conditions and severe malnutrition at the Toshiba Tsurumi plant and internment camp.

On the tour, it was explained that there were cases when POWs who were unable to move anymore because of their poor health were beaten to death by guards. Many died in U.S. air raids.

After hearing the explanations and viewing the site of the former factory, Robert and the others visited the location where the barracks of the nearby internment camp once stood.

Sasamoto and her research team revealed that there had been unseen interactions between the POWs and a family with a girl named Yoko Koshida, then 16, who lived next door to the camp in the form of the melodies coming forth from the schoolgirl's piano.

Yoko, who was practicing the instrument with the aim of going to music school, told the story of one day seeing from her window POWs on the roof of the camp intently listening to the sound of her playing. Their numbers increased day by day, she said. Robert expressed the deep emotions he felt upon hearing this account.

At the end of the war on Aug 15, 1945, the POWs were released and received relief supplies from the Allied Forces.

Later, one of the former captives visited the Koshida home to deliver chocolates, canned foods, soap and other items, saying, "This is for your daughter."

On another day, about 20 of the men visited the home again, this time with bags of sugar and other goods. They thanked the girl for her musical interludes, adding that they were "comforted by the sound." Shortly after, they were on their way home.

On their trip, the Stenverts visited the Koshida home, too. Although Yoko died two years ago, they met with her 69-year-old daughter and other family members. Robert also was able to see up close the same piano that the girl had practiced on.

"How happy my father would have been to have visited here if he were alive," he told the family.