There are lots of ways to be a diffusion line. MM6, the lower-priced companion to Maison Martin Margiela, exists in a curiously fetishistic relationship to the premium line. Witness, this season, the introduction of MM6 T-shirts that feature photographs of the Maison Martin Margiela flagship store in Paris, the street it's on, and its "open for business" sign. There's almost a family romance in that—the younger sibling staring up, with adoring eyes, at her older brother, trying to steal his impossibly cool tricks.

MM6 does fine by those tricks, as its many customers know. The brand's latest collection comprises a mix of typically wearable workwear-inspired clothes, multifunctional, deconstructed pieces, and un-basic daywear. The standout items tend to be the seemingly simplest ones—a T-shirt dress in cloudy, hot pink parachute nylon; a fitted beige jumpsuit with a low V neckline and a slit through the back; a pair of slouchy, kimono-belted navy trousers; and a slinky, back-draped dress. You don't have to be a Margiela freak to get the appeal of these garments. Elsewhere, the MM6 designers seem to struggle a bit with their multifunction mandate, though they've managed one clear success in a marbled leather jacket, cut like a denim one, with a zip-off portion that also works as a belt. Very cool, little sis.