What is True in History
- The Setting: Hashima Island (nicknamed "Battleship Island" because of its shape) was a real undersea coal mining facility operated by the Mitsubishi Corporation off the coast of Nagasaki.
- Forced Conscription: During World War II, hundreds of Korean (and Chinese) civilians were lured with false promises or forcibly taken to work in the mines.
- Brutal Conditions: Laborers worked in narrow shafts up to 1,000 meters deep under extreme heat exceeding 40ยฐC (104ยฐF). Many died from accidents, exhaustion, starvation, or gas poisoning.
- Cremations: Historical records and survivor testimonies confirm that those who died on the island were often taken to a nearby island (Nakanoshima) to be cremated.