Our verdict: four stars

Ever heard of Genesis Potini, a chess champion from New Zealand? After watching this heartbreaker of a biopic, chances are you will never forget him.

When first we meet Potini his bipolar disorder has led to him being hospitalised once more. Allowed out of care into the so-called care of his brother, a gang leader, and told to avoid stress at all costs, Potini hits one snag after another. Chiefly, he is worried about his nephew, who looks like going the way of his father. The only good thing in Potini's life is the chess club where he volunteers as a tutor.

Guiding these waifs and strays, and possibly steering them towards the championships, gives his life meaning and a joy it has long since lacked. But how strong can he stay mentally when his home life starts to fall apart again?

James Napier Robertson's picture is so much more than another inspirational teacher tale. Drawing deep on its New Zealand setting and the Maori culture, it has a otherworldly, heartfelt feel to it that makes it instantly endearing. We care about Potini from the off; we are intrigued by where he comes from and keen to know where he is going.

All credit to Cliff Curtis in the title role for bringing a difficult role to life with such subtlety and intelligence. You will know Curtis's face from such Hollywood blockbusters as Three Kings and Training Day.

Accustomed to being in the background in Hollywood, he is on home turf here and he comes into his own. It is an outstanding performance that may be hard to watch at times, but is simply not to be missed.

Showing Glasgow Film Theatre, Friday, February 20 (11.00)