"It's the 1920's, 1930's," mused Daisuke Obana, the designer of the cult Japanese menswear label N.Hoolywood. "Men were well-dressed, in classic looks, with very good hairstyles." Well-kempt, perhaps, but not so well-behaved: The men Obana took his cues from this season were convicts and derelicts. Police Picture, he called his Spring 2011 collection (the first he's presented at New York fashion week): It's a polite way of saying "mug shot."

The setup made for one of the most interesting presentations so far this season: First, there was a gallery, filled with mug shot-style portraits by Katsuhide Morimoto, and at the far side, a long, thin picture window. Elbow your way past rapturous Japanese cameramen and you could watch the models, one by one, march into view, turn to face the front and then in profile, as a flashbulb light went on and off. These were mug shots in action, modeled by guys who looked far rougher around the edges than your usual runway waifs.

Before founding his line, Obana was a vintage obsessive, and he honed his eye for perfect period detail by raiding secondhand shops. His wide-cut pants are made of rough twill and denim—the kind of rough twill and denim that only gets made in top-of-the-line Japanese factories, of course. Suit jackets are boxy, with high-breaking lapels and slight, cocooning curves.

But those are just the looks from the way in, so to speak. The best section of the show featured refractions of jailbird garb: inmate-issue striped jeans, tops, and jackets. These are less faithful to the historical record: Graphic black and white stripes shoot every which way—vertically, horizontally, meeting in chevron V's. In other words, here's a bunch of stylish guys who look like trouble, hanging out in cool Japanese uniforms.

Prison's starting to sound like an exclusive club. How do you get in?