Japan's multibillion-dollar pornography industry suffered a shock last month after police arrested three men connected with one of the country's top talent agencies, in a rare crackdown on illegal practices in the business.

Investigative sources said the trio were arrested on suspicion of dispatching a woman in her 20s to work with a video producer over two consecutive days in late 2013 during which she was coerced into engaging in a sex act.

Those who cover crime in Japan know this problem isn't new — it has just been a while since the police did anything about it.