Girl power is growing in the Japanese film industry, driven by strong B.O. numbers of films with young female stars for young female auds.Last year the strongest were delivered by “Nana,” Kentaro Otani’s female buddy movie based on Ai Yazawa’s popular shojo manga (girls’ comic). Released in early September, the film has grossed more than $34 million, while making stars of real-life popster Miki Nakajima, playing a sneering punk rocker, and newcomer Aoi Miyazaki, playing a chirpy country girl who becomes the rocker’s unlikely friend, roommate and confidante. The film’s theme song, sung by Nakajima, hit No. 1 on the charts, as did the 14th and latest paperback in the “Nana” series. (Sales of all 14 have topped 27 million copies). Meanwhile, “Nana” has shown that a movie based on a shojo manga — a genre that long took second place as film material to manga for boys — can appeal to a wider aud than the original comic’s fans. Spurred by “Nana’s” success, a spate of shojo manga films are on their way to theaters — or have already arrived. The first is “Angel” (Tenshi), based on Erika Sakurazawa’s comic. Kyoko Fukada (Kamikaze Girls) plays a mute angel who helps lonely hearts in a Tokyo neighborhood find romance. Mayumi Miyasaka directs, while Masatoshi Nagase (“Loved Gun,” “Mystery Train”) and Naomi Nishida (“Christmas in August,” “My Secret Cache”) co-star. Shochiku released “Angel” nationwide on Jan. 21. The hottest shojo manga ticket, however, is expected to be “Honey and Clover,” an ensemble drama about the turbulent loves and lives of five college students. Chika Umino’s eponymous manga has sold more than 4 million copies in eight paperback editions, while Fuji TV’s latenight animation based on the comic became a hit with insomniacs, particularly those the same age as the characters. The film, which stars Sho Sakurai of the pop band Arashi and is directed by TV commercial whiz Masahiro Takada, is skedded for a summer release by Asmik Ace. Meanwhile the studios are hot on the hunt for new Nakajimas and Miyazakis, with three — Shochiku, Toho and Kadokawa, recently holding mass auditions for young female stars of the future. Shochiku’s contest, called “Stargate,” recruited more than 10,000 hopefuls. On Nov. 23, Shochiku announced four winners, who will receive studio talent contracts. “It’s the first time we’ve done something like this in 10 years,” commented “Stargate” producer Hiroshi Fukasawa. “Why now? Japanese movies are doing well at the box office so we’re making more of them.” To cast its beefed-up slate Shochiku would rather dip into its own talent pool than that of the big agencies’. “If we only go to the agencies, we develop stars for them, not for ourselves — so what’s the point?” says Fukasawa. This, he adds, goes for male talent as well. “We’re planning a similar contest for boys,” he says. For the moment, though, it’s girls who are in bigger demand. Call it the Nana Effect.