Kazuhiro Soda made his name with his first documentary film "Campaign," which follows the director's former classmate Kazuhiko Yamauchi as he campaigns for a city-council seat in Kawasaki, Kanagawa Prefecture. The film was screened at the Berlin Film Festival in 2007, broadcast on TV in around 200 countries and last month, in May, won the prestigious Peabody Award, which is often referred to as the Pulitzer Prize for radio and broadcasting.

His second feature documentary, "Seishin" ("Mental"), breaks a taboo and opens — as the director puts it — "an invisible curtain" between the so-called "healthy" and "the ill."

The day after he finished filming "Campaign," Soda stepped inside Chorale Okayama, an outpatient mental clinic in Okayama Prefecture, to see the world inside the curtain.