The authorities believed the comfort system would enhance the morale of the military and help prevent soldiers from committing sexual violence toward women of occupied territories, which became a real concern after the infamous Nanjing Massacre in 1937.
Though around 80 per cent were Korean, women from Japan, Taiwan, the Philippines, Indonesia, Burma and the Pacific islands were also used as comfort women.
The world's first ever footage of Korean sex slaves used by Japanese soldiers during WWII has emerged.
On other occasions, Medford would have another worker fetch Maldonado from solitary confinement and then bring her to her office for sexual encounters.
Maldonado says the other worker, a tour supervisor named John Ike, and other staff members mentioned in the lawsuit, knew what was going on in the office. While he was being sexually abused by Medford, Maldonado says he knew of at least one other female supervisor who was grooming a male inmate at the center. Maldonado says that the male tour supervisor, Ike, told him that female guards having sex with male inmates was 'business as usual' at the center.
A team from Seoul University and Seoul Government matched the footage outside the building to pictures and identified the women by their clothes and facial appearance.
Sung Kong Hoe University professor Kang Sung-hyun, who participated in the study, said: 'Their appearance, such as the bare feet, suggest they were enslaved.'Due to a long-standing dispute over Japan's wartime sexual slavery, it became crucial to come up with evidence.