The Sinking of the Lisbon Maru – rejected earlier this week as China’s official Oscars contender – recounts a terrible and forgotten tragedy. Director Fang Li explains why, 80 years on, the story still arouses fierce passions

A little-known tragedy from the second world war is the subject of a documentary that has been a surprise hit in China and is the country’s pick for two Academy Awards – although it has already been disqualified from one of the categories.

On Monday, it was revealed that The Sinking of the Lisbon Maru, which had been selected by China as its entry for the best international feature prize at the Oscars, had been deemed ineligible. The competition’s rules state that a film in that category must have “a predominantly (more than 50%) non-English dialogue track”.