Historians have discovered that as many as 1.2 million Koreans were tricked into working for the Japanese during World War II. A search that has been ongoing for over a decade has led to the discovery of remains from 2,750 Koreans that died while working in Japan. The families of these workers were never allowed to know the location of the workers remains. These workers were forced to work in factories, mines and airfields. The government in South Korea is currently trying to contact families related to the remains they found, but so far they have only found 153 relatives.
See "Remains of Nearly 2,750 Korean Wartime Laborers Found in Japan, South Says", Choe Sang-Hun, November 4, 2015