When Katsumi Sakaguchi quit working as a documentary filmmaker in the spring 2008 to look after his mother Suchie, he thought he was doing the right thing. Then 78, Suchie was suffering from what Sakaguchi describes as "mental confusion" following the death of her daughter from cancer two years earlier and the recent hospitalization of her husband, who later died of pneumonia.

"I had to choose between my work and my mother, so, of course, I chose my mother ," says the veteran documentarian, whose film "Hoyo" ("Walking with My Mother"), about his subsequent four years of caring for Suchie, premiered at last year's Tokyo International Film Festival.

"She was the one who bore and raised me. I felt I had to do it," he says.