Superficially, this is a very clean looking film. It’s anime, it’s a high school drama; school children are drawn with clean lines and bright colours in bright settings with mostly clear blue skies. Beneath that clean veneer, though, lurks dirt. Psychological dirt. Bullying. Its effect on the self-worth of the victimised and the perpetrator. Self-loathing. Suicide.

Shoya Ishida (voice: Miyu Irino) has marked the days up to the 15th on his calendar and torn off the numbers after. He does his last day at work, sells his possessions, leaves the money with his mum to pay off an outstanding debt and goes out to jump off the local river bridge. Flashback: in elementary school he is a troublemaker who picks on the new girl in class Shoko Nishimiya (Saori Hayami), who happens to be deaf. Nishimiya tries hard to be nice to her classmates asking them to communicate with her via the notebook and pencil she carries around. Perhaps she tries a little bit too hard and apologises once too often. In the playground, Ishida throws little stones at her and when she tries to be friendly, he literally lobs dirt on her face. Naoka Ueno (Yuki Kaneko) encourages his actions. Eventually he’s hauled up by the principal for repeatedly plucking Nishimiya’s hearing aid off (to the tune of some eight sets).

Shunned by others for his bullying, Ishida stops interacting with them and withdraws. This is represented onscreen by the extraordinary graphic device of an ‘X’ over the faces of his fellow schoolmates whenever they appear. It’s a very powerful way of expressing his isolation. Five years on, wrecked with guilt about his treatment of Nishimiya, he learns sign language and decides to befriend her and to make amends…

His fellow elementary classmates too are struggling to come to terms with their varying degrees of complicity in aiding or condoning his bullying. They may be children and this may be animation, but these are complex characters, deeply scarred, and yet still trying to find ways to move forward and live.

This film may well broaden your idea of what animation is capable. It’s nothing like Disney and equally it’s light years from Japanese SF action fest Akira (Katsuhiro Otomo, 1988) although it likewise started life as a manga and concerns teenagers. These teens, however, are not rebels against the system but simply very ordinary, screwed up kids. If this were British we’d probably have made it as a live action drama, possibly for television. It feels long at 129 minutes, but that running length allows for complexities of character and plot that a shorter running length would have sacrificed.

In the end, you get to feel how a disabled person struggles to fit in as much as you do a bully’s remorse for what he’s done against an ongoing background of other interconnected minor characters. It’s a very dirty movie, but it’s the internal dirt of the mind that’s under observation here. A challenging and demanding work, it’s also an extraordinary and groundbreaking piece of animation unlike anything else you’re likely to see on the screen this year.

Beyond that, it’s innovative on another level: it will play some UK cinema screenings with hard of hearing subtitles to allow hard of hearing audience members to experience the full film, including sound effects and music. Which seems highly appropriate given its subject matter.

A Silent Voice is out in the UK on Friday, March 17th, with exclusive screenings nationwide on March 15th.