A Japanese hip-hop musical? How about a samurai swashbuckler set on the streets of Compton, California? But Sion Sono makes his new film, "Tokyo Tribe," more than an oddity of cultural appropriation. Truth be told, I felt queasy as the story, based on a manga by Santa Inoue, began to unfold in a crime-ridden near-future Tokyo, with the "tribes" (gangs) of the title ruling the streets as the cops complicitly look on. Was this, I wondered, Sono's twisted idea of a rap paradise? Was he grossly stereotyping or was he not?

Before pronouncing Sono guilty (a verdict this career-long violator of taboos, PC or otherwise, would probably shrug off), please note that the film's music is mostly supplied by BCDMG (Big Crow Dog Music Group), a collective of Japanese rappers. (Beethoven's Fifth is one prominent exception to the rule.) The film also stars pro rapper Young Dais (real name Daisaku Shimada) who plays the leader of the Musashino Saru tribe, which would rather make love than gang war.

My knowledge of rap history is slender, but even this troglodyte baby boomer is aware that rap has long since become an international musical language, much like Sono's beloved Western classics. Also, from the evidence on the screen, Sono's cast, non-rappers included, have thoroughly assimilated the whole hip-hop thing, from their stylishly coordinated street looks to their easy fluency with the nonstop lyrics. The film is less a goofy parody than a smartly, madly staged rap celebration.