Ripped from the headlines, this docu-drama from Japanese director Hirokazu Kore-eda is based on a real 1988 event prosaically known as the "Affair of the Four Abandoned Children of Nishi-Sugamo". In this fictional retelling, 12-year-old Akira (Yûya Yagira) has to look after his siblings when his mother (bonkers Japanese TV personality YOU) absconds, leaving them in a tiny apartment with just a few thousand yen. As Akira struggles to keep the family going, the children gradually slip into a dreamlike existence of unlimited playtime, instant noodles, and confused distress.

Shooting chronologically over the course of 12 months, Kore-eda crafts this real-life story into a moving docu-drama about the loss of childhood innocence. With just one principal location - a tiny apartment - and four non-professional child actors sharing the burden of the film's focus, it's a dazzling technical achievement: instead of producing a conventional script for the children, Kore-eda simply explained their lines to them on-set each morning and let them improvise.

"A DISTURBING WAKING DREAM"

Sharing the same sense of melancholic stillness as the filmmaker's last feature - Distance, a brooding drama about the aftermath of a terrorist attack on the Tokyo subway - this confirms Kore-eda's talent for documentary-style fictional dramas. Despite citing Tokyo's underclass of unregistered - often abandoned - children as his chief influence, Kore-eda actually seems more interested in the stunted emotional development of these abandoned children as they degenerate into scruffy urchins.

The terror of social exclusion in a culture that places so much emphasis on group mentality is more than apparent, but it's Kore-eda's flatness of tone that proves so challenging, as he captures the emptiness of these lives without parental structure. In the end, though, neither the inevitable tragedy nor the tender moments of comedy (a pair of children's shoes that squeak on each step, YOU's bizarre performance) are enough to shatter the film's placid surface. A disturbing waking-dream.

In Japanese with English subtitles.