In 1999, commercial director Yuji Dan started work on his first feature. “Boy” was an ambitious youth drama and state-of-the-nation address inspired by the Japanese government’s controversial move that year to give legal recognition to the country’s national flag and anthem. Evoking the radical spirit of Japan’s Art Theatre Guild and the New Hollywood movement, it was a film that sounded great on paper. The only problem was, its creator couldn’t seem to finish it.

Dan shot “Boy” intermittently until 2003 and screened a rough cut of the movie at Germany’s Nippon Connection festival in 2007. It then languished for the best part of two decades, before the director finally managed to complete the damn thing.

The film’s tortuous gestation has imbued it with an aura of mystery, suggesting a homegrown answer to Francis Ford Coppola’s “Megalopolis” (did I mention that “Boy” is also three hours long?). Yet it’s more curate’s egg than lost classic, albeit a fascinating time capsule from a troubled moment in the country’s not-so-distant past.