“Korean workers had to clean up the dead," Mr Shim, the director of the Hapcheon branch of the Korean Atomic Bomb Victims Association, tells BBC Korean. "At first they used stretchers, but there were too many bodies. Eventually, they used dustpans to gather corpses and burned them in schoolyards.
According to the Korean Atomic Bomb Victims Association, the Korean fatality rate was 57.1%, compared to the overall rate of about 33.7%. About 70,000 Koreans were exposed to the bomb. By year's end, some 40,000 had died.
Ms Ichiba notes that Japanese textbooks still omit the history of Korea's colonial past - as well as its atomic bomb victims – saying that "this invisibility only deepens the injustice". This adds to what many view as a broader lack of accountability for Japan's colonial legacy.
"Memory matters more than compensation," he says. "Our bodies remember what we went through… If we forget, it'll happen again. And someday, there'll be no one left to tell the story."