Japanese filmmakers are specialists when it comes to stories about emotional repression. And hand in hand with their expertise goes a fascination with the dynamics of the family. It's a fascination tinged with wistfulness caused no doubt by the long hours that Japanese salarymen spend in their offices at the expense of their lives as husbands, fathers and sons.

The master of the genre was Yasukiro Ozu, whose quietly contemplative films about Japanese home life did so much to boost the international reputation of the country's cinema in the 1950s and '60s and Kore-eda Hirokazu, director of Like Father, Like Son, is often touted as Ozu's direct heir. He, too, has staked out the domestic landscape as his territory - although his style is rather more nimble than that of Ozu, who kept the camera permanently set just above floor level for reasons which have kept critics wrangling about them for decades.

Here, Kore-eda has chosen a classic theme. Two babies are switched in the hospital where they're born and taken home by the wrong parents and it's years before the mix-up is discovered.

Like all classics, it's an infinitely adaptable scenario. We saw it last year in The Other Son, played out against the Arab-Israeli conflict. Here, it's moulded into a tale about class differences. One of the fathers, Nonomiya Ryota (Fukuyama Masaharu), is an affluent and ambitious architect with a demure wife and a six-year-old son who seems to have inherited his mother's gentleness, much to Ryota's frustration. And the other, Saiki Yudai (Lily Franky), is a happy-go-lucky appliance salesman from one of Tokyo's poorer suburbs. He and his wife run a shambolic household. Yudai, however, always has time to play with his four children and they're more outgoing because of it. Kore-eda raises this stereotypical set-up beyond the level of cliche with the exactness of his observations, the performances he gets from the children and his actor's skill in investing the personalities of the parents with a healthy unpredictability.

There are times when the script seems just too schematic - as if Kore-eda has decided that we should all sit still while he lays out the nature versus nurture debate.

Then the small truths which enrich each scene take over.