It seems half the designers currently working in menswear are experimenting with proportions they're calling "couture." They mean the exaggerated roundness and cocooning volumes pioneered by Cristóbal Balenciaga half a century ago. Roundness in clothing is basically in the public domain, but it's hard not to feel the house Balenciaga built has some claim on its own creation. It, too, showed voluminous, egg-shaped menswear for Spring 2013, citing house codes as always, but mentioning postwar Japan as well, at the nexus of East and West. The guiding spirit is Ryuichi Sakamoto, the avant-garde Japanese composer who has, at times, stood literally at the intersection of the two. (He costarred in Merry Christmas Mr. Lawrence with a middle-period David Bowie.)

The collection is Japanese in key fabrics (like a textured cotton/silk seersucker) and Japanese in key shapes (as in the robe-like oversize kimono coats). It's also, thanks to exaggerated proportions, like those of an extra-long, single-button suit jacket, the house's most challenging menswear proposition in several seasons. Contrasting the larger volumes is a new austerity. Here the new-classic leather jackets brought back season after season get their sparest treatment yet: all clean lines and no lapels, just a banded detail that looks like nothing so much as a car grille.

A pixelated floral cried loudest for attention among the prints, but it was actually two others—a moiré, borrowed from the archive, on silk taffeta, and a kind of electric stripe—that hit on the heart of things. They fairly vibrated. Push and pull. You couldn't ask for a better capsule description of the collection.