The Japanese government had enslaved, raped and murdered thousands of Korean women during WWII. These women were rounded up in large numbers and shipped to military camps to "comfort" the men there. The first-hand accounts from the few survivors were terrifying and testified to the brutality they've endured.
Even decades afterwards, they suffered severe emotional and physical scars. Many became involved in successful campaigns to force the Japanese government to formally apologize and acknowledge its role in the slave trade.
In 2015, the Japanese government sent $8.3 million in reparations to the few survivors. Recently, actual footage of the comfort women surfaced on the internet, opening old scars.
Sources:
http://www.koreatimes.co.kr/www/nation/2017/07/120_232456.html