Throw together a nerdy guy with a superpower, a purehearted girl who falls for him and his best friend who’s been secretly in love with him since childhood, and you’ve got a typical setup for a love triangle, variations of which can be found in many a manga and movie. In Keiichi Kobayashi’s quirky rom-com “Love Is Light,” which was adapted from a manga series by the mononymous Akieda, this story plays out in ways fresh and charming, despite its familiarity. Wisely, the film focuses more on its protagonist's tortured personal journey than his predictable final destination. Formidably smart and excruciatingly polite, university student Saijo (Fuju Kamio) has an unusual intellectual interest: the definition of love, and not only in the dictionary sense. His curiosity stems from his mysterious ability (though he considers it a curse) to gauge feelings of love in the women around him by the tiny globules of light they emit. But what, he wonders, does this light really mean? Mere sexual attraction or something more? His confidante is Kitashiro (Nanase Nishino), a childhood friend who calls him by the nickname “Sensei” (“Professor”). Though she has carried a torch for him since their elementary school days, she is resigned to permanent friend status — and never emits a single light bubble. Then one day, Saijo meets Shinonome (Yuna Taira), a girl in his college class as earnest and unworldly as he is. At Saijo’s suggestion, the new friends begin exchanging a diary in which they inscribe their thoughts on the knotty problem of love. We soon see that the pair are a perfect couple, especially after Shinonome innocently confesses her affection for Saijo and light begins to gently dance around her. But just as love is about to bloom, Yadorigi (Fumika Baba), a classic mean girl who specializes in stealing the boyfriends of other women, targets Saijo as her next conquest. Kobayashi has been scripting and directing offbeat films themed on love and populated with likable oddball characters since his feature debut “About the Pink Sky,” which received the best picture award in the Japanese Eyes section at the Tokyo International Film Festival in 2012. In “Love Is Light,” however, Saijo and Shinonome are so out of the flesh-and-blood ordinary that it’s hard to imagine them as anything but minds and spirits intertwining. Also, Kitashiro is too forbearing as the hero’s best pal, though Nishino plays her with nuance and sharp comic timing. Baba’s portrayal of Yadorigi, as she insouciantly elbows her way into the film’s romantic triangle, refreshingly defies the “designing woman” stereotype. Some of her lines may be on-the-nose — while drinking with Saijo, she flatly confesses “I’m a predator” — but she is also bracingly matter-of-fact. “If you think it’s love, it is,” she proclaims to members of her clique. “Love is a battlefield,” she later tells the impressed Shinonome. In this sweet but all-too ethereal film, she is a funny and needed reality check. And, yes, those little balls of light bob around her, too.