From 1971 to 1988, Nikkatsu studio’s Nikkatsu Roman Porno label for soft-core adult films was a training ground for young directors who went on to have thriving mainstream careers. Such filmmakers include Shusuke Kaneko (“Death Note,” 2006) and Yojiro Takita (“Departures,” 2008). The label also generated films later regarded as classics.

Hideo Jojo’s latest films, “S-friends” and its follow-up “S-friends 2,” are both produced by Nikkatsu but are not revivals of Roman Porno, which catered to the tastes of male audiences, not infrequently with lurid scenes of sexual abuse. Rather, they are based on a manga series by Yoriko Minato targeted at women.

A prolific maker of films with an erotic edge, including the charming “Love Nonetheless” and the skin-crawling “To Be Killed by a High School Girl,” Jojo directs with an affinity for his female-centered material and discretion in its many sex scenes, which are steamy but not crudely exploitative.

Its title an abbreviation of “sex friends,” “S-friends” has the setup of a romantic drama for grown-ups: Shoko (Aika Yukihira), the divorced mother of a teenage daughter, attends a class reunion where she reconnects with her high school boyfriend, the handsome Kazuki (Sho Aoyagi). Now the head of an obstetrics and gynecology clinic, the similarly single Kazuki is quite the catch, but Shoko has no intention of rekindling the flames of their adolescent romance.

Here is where a slow build to passion and romance might begin in a straight drama. Kazuki, though, issues a blunt invitation once they are alone: “Do you want to have fun?” And Shoko, caught up in the moment, agrees. Soon after, they are making enthusiastic love in a hotel.

Such cut-to-the-chase storytelling is standard for adult fare, including the “pink” (soft-core) films that Jojo has made by the dozens. It is also what the general run of humanity would consider an erotic daydream.

But in between all of the sex scenes, which occur with metronomic regularity every 10 minutes or so, the film is refreshingly reflective of a woman’s point of view. Shoko is slipping into middle age, working a low-paid part-time job at a call center and trying to be a good parent to her daughter. This does not describe the average porn protagonist.

The film is also filled with real-life problems and emotions that adult films usually skim over. Shoko finds herself in pain after her first sexual encounter in ages. In a comic interlude, Kazuki gives her a gynecological exam in his office and tells her to go easy the next time around.

More seriously, Shoko can’t help her unruly feelings and nagging doubts while reluctantly accepting Kazuki’s offer to be strictly “sex friends.” When she learns that Kazuki has a similar agreement with another former classmate, the bubbly Hanae (Momemi Katayama), she is shocked. And when Hanae suggests a menage a trois, Shoko turns her down. Later, she confesses, “I have no confidence in my values.” But she can’t quit Kazuki.

The plot stirs in more complications, some turgidly melodramatic and problematically libidinous, from Kazuki’s turbulent marital past to Shoko’s relationship with her creepily infatuated boss (Shinya Niiro) at the call center. Though he wants to marry her, Shoko instead suggests a deal: He can bed her in exchange for promoting her to full-time status.

Marriage, she can do without. But can she also do without the troubled, promiscuous, undeniably seductive Kazuki? We’ll have to watch “S-friends 2,” in theaters now, to find out.

S-friends
Rating
Run Time99 mins.
LanguageJapanese