Tetsuya Nakashima’s films are growing increasingly dark and disturbed. 2004’s Kamikaze Girls was a candy-coloured poptastic riot; Memories of Matsuko, in 2006, was a tale of mental collapse leavened by surrealistic flights into a more cheerful dreamworld; Confessions – now slated to be Japan’s official entry in this year’s Oscars – is a tightly controlled, vicious and intense account of cruelty, murder and revenge. It might be built out of some fairly standard Japanese movie furniture – a school setting, a smart-but-evil boy, bullying, a mobile phone-mediated and death-fetishising youth culture – yet it’s a work of powerful originality and psychological truth.

In the film’s opening segment, teacher Yuko (Takaku Matsu) stands at the front of her middle school class and tells them about the recent death of her four-year-old daughter, drowned in a swimm­ing pool. The police judged it an accident but, Yuko says, it was murder; what’s more, she accuses two of the children – a psychotic genius with a mother fixation, and a bullied weakling – of being the killers. Because of their age, she goes on, the law is powerless against them, and so instead she has injected HIV-infected blood into the milk cartons they just drank, in order that over the next few months they learn to appreciate the value of life. The rest of the film is about a fixation with death, as Yuko’s revenge plays out. Gradually, Nakashima reveals the twisted depths of his characters, teasing out the flaws that pull them all down into hysteria, savagery and despair.

As in Memories of Matsuko, there is a strong emphasis in Confess­ions on storytelling and delusion. “You’re all so good at lying”, Yuko says to her class in her opening speech; and, indeed, the characters deceive others and themselves, with their doubtful truths being woven into the story right from the start, when what was thought to be an accident becomes a murder. The film is told by a series of narrators, or rather as a series of ‘confessions’ which run into each other as each character attempts to exert some power over the story, to be the star of his or her own drama. The solipsistic, self-pitying, competit­ive world of childhood is of course the perfect setting for this. And Nakashima the filmmaker is himself complicit, refusing to give us an overview of events, presenting flashbacks as they appear in his characters’ heads.

With its initial set-up of Yuko calmly addressing the children, Confessions takes a while either to emerge as believable or pick up pace. But its palette of cold blues and greys, its insistent soundtrack, and Takako Matsu’s still, intense central performance, means psych­ological tension and a sense of barely-contained violence build steadily as the film’s lonely characters are funnelled towards an explosive climax.

Nakashima is a visually and structurally inventive filmmaker, and in Confessions he gets some strong performances out of his young cast. He also proves himself a masterful storyteller with a disquieting insight into the darkest recesses of the human psyche.