Police took action against 40 people for human trafficking offenses including forced prostitution last year, up by 10 from a year earlier, official data showed Thursday.
The 40 suspects included those involved with crime syndicates and in the adult entertainment business.
The number of human trafficking cases reported in the National Police Agency data declined by 10 from the previous year to 36.
The number of human trafficking victims identified in the cases, mostly young Japanese women, as well as victims from other Asian countries, stood at 25, down 17 from a year earlier amid a crackdown by the government on sexual exploitation, including the coercion of women into performing in pornographic videos.
Of the victims, 18 were Japanese nationals, while four were Filipinos and three were Thai.
The youngest victim was a 9-year-old girl, whose mother was arrested for alleged crimes related to a video she produced featuring an image of her naked daughter.
In a separate case, a company executive was arrested on suspicion of introducing a 19-year-old aspiring fashion model to a production company that forced her to appear in a pornographic video.
An NPA official warned potential victims to be wary of being tricked into becoming involved in prostitution, the sex industry, or forced labor, saying some fell victim through social media.
Japan's legal definition of human trafficking is derived from the United Nations, which states that trafficking involves "the recruitment, transportation, transfer, harboring or receipt of persons by the threat or use of force or other forms of coercion" for the purpose of exploitation.