A film about an elderly man's struggle following the March 2011 earthquake and tsunami disasters received a top award in the documentary category at the 37th Hong Kong International Film Festival on Tuesday, said its director, Kaoru Ikeya.

"Senzoninaru" ("Becoming an Ancestor"), with the English title "Roots," follows the postquake life of Naoshi Sato, 79, until he eventually succeeds in rebuilding his home, half of which was destroyed in the disasters. Sato, a resident of Rikuzentakata, Iwate Prefecture, lost his son in the tsunami.

"Many members of the audience told me that they were cheered up (by the movie)," Ikeya said.

"It is because the efforts by Naoshi were accepted in Hong Kong as well," he said of winning the Firebird Award, a top-division prize.

At the 63rd Berlin International Film Festival earlier this year, the movie received a special mention by the Ecumenical Jury, which gives awards independently of the festival's secretariat.

The movie, which has been released at a limited number of theaters in Japan, is expected to hit more screens soon.