Genki Kawamura has the kind of resume that could make anyone feel inadequate. As a producer, he’s been involved with some of the buzziest Japanese movies of the past two decades — from “Train Man” to “Confessions” to “Your Name.” When he turned his hand to writing, his debut novel, “If Cats Disappeared from the World,” became an international bestseller.

“A Hundred Flowers” marks Kawamura’s debut feature as a director — and it would be nice to report that he’d finally found something he didn’t do well. So it’s with a heavy heart that I confess: This is one of the most engrossing big-screen experiences I’ve had all year.

Adapted from the director’s own novel, the film may be an intimate drama with only a few significant characters, but it’s emphatically worth watching in a theater.