Able-bodied Korean men were shipped out to the Japanese archipelago to work in the mines and factories there during WW II. Read these first-person accounts by others who was there, a Japanese high school student who were also dispatched, together with his entire class, to work alongside the Korean men in iron mines. The two groups did work together in the open pit mine, and did engage in some fraternizing. However, at the underground mine, it was the Koreans who unhappily worked in the shafts, while the students worked aboveground transporting the ore.
The Koreans differed from the students in two other ways. First, they received wages. Koreans acknowledged this in the lawsuits, where the plaintiffs demanded unpaid back wages, among other things. Second, they had an out. They could volunteer to serve in the Imperial Army; after all, they were Japanese citizens. Not many did, of course, as the small number of ethnic Koreans enshrined in Yasukuni attests. This also meant, though, that they were better off than the typical able-bodied Japanese-Japanese male, who, if given the choice, would surely have elected to serve the war effort from behind.
How were working conditions like for the Koreans? If the open-pit and underground narratives are any indication, they varied significantly with the circumstances—just like the experiences of the soldiers in the Imperial Army. In one example chronicled by the dreaded Special Police of all people, 292 of the 383 Koreans who had been conscripted to work in a nickel mine had run away. The officer making the report complained that the Koreans were being taken in by Japanese businesses, who apparently were offering better working conditions than the mine.
And where there are war efforts and able-bodied males, there are bound to be “comfort women”; the Japanese mines and factories were no exception. Perhaps the high school students were too naïve to notice, but a pro-Korean advocacy web site takes note of their existence on two occasions, 40 Korean women and three Japanese women respectively, both apparently servicing Korean laborers.
I’ll leave it at that for now.