When Wong Kar-wai’s “The Grandmaster” — a martial arts epic about Ip Man, who taught Bruce Lee kung fu — opens today, some of his story won’t be seen on US screens. That’s because, sources familiar with the production say, the Chinese government’s censorship board demanded certain biographical details in the movie be omitted. In the lavish biopic, southern China’s top martial artist, Ip, is shown fleeing to Hong Kong in 1949, leaving his family. But the film neglects to mention that he left because he was also a police officer who was active with the Kuomintang — a rival to the Communists in the Chinese civil war. An Asian film buff explained of the omission: “Stories for films shot in China must be submitted to [a] censorship board for approval, top filmmakers like Wong included. There’s a piece of the story he would not be allowed to include in the movie. Ip Man went to Hong Kong because he was an enemy of the state.” The source added Chinese directors must routinely cut details disagreeable to the government to get their films made. Either way, the flick’s gained A-list Hollywood fans, including Martin Scorsese and Samuel L. Jackson, at advanced screenings.