Recent news that an anime film adaptation of the smash-hit "Demon Slayer" series has been rated R (Restricted) ahead of its U.S. release has made some wonder how the movie, known for its occasional depictions of violence, was rated in its home country, and prompted an even broader question: What do film ratings really mean in Japan?

An independent organization called the Film Classification and Rating Organization, commonly known as Eirin in Japanese, is tasked with rating films in Japan.

Rebranded in 1956 from its previous incarnation, Eirin currently has eight raters with experience in the movie industry who vet more than 800 submissions, including films, trailers and promotional flyers, annually. It has four rating levels: G, PG12, R15+ and R18+.