Anonymity is the nemesis of pop. History is filled with earnest, well-meaning bands who did whatever they could to keep the music up front and the personalities in the background, often to the point where they wouldn't even reveal their names (like early Pavement). But unless you intend to toil in obscurity for the rest of your days or advance anonymity itself as your main selling point (the Residents), you're destined to fail.

The OlO: In search of anonymity

This is the dialectic behind the current underground movement known as post-rock, which is essentially progressive rock made respectable. During the heyday of prog rock, people like Peter Gabriel, Robert Fripp and whoever happened to be in charge of Pink Floyd at any given moment practiced a high-minded theatricality that many believe was directly responsible for the emergence of punk as an antidote to creeping pretentiousness.

But for every masturbatory show-off like Keith Emerson, there was a willfully weird art student like Holger Czukay, the genius behind the influential German prog-rock collective Can. Can's members were not anonymous, but the music stood forthrightly on its own, somehow detached from its creators.

Post-rock offers music that's more accessible than Can's. What bands like the Sea and Cake and Gastr del Sol share with their European forbears is an ability to stand back from their compositions and fade into the wallpaper. In fact, post-rock's detractors (New York rock critics, for the most part) usually say that since the music is wallpaper, too, the anonymity is deserved and not just desired.

But that's exactly post-rock's appeal, if not its saving grace. Devoid of attitude, the music lets you like it for what it is -- or not like it for what it is. In a sense, it doesn't care. It's free jazz without the virtuosity; jam music without the song structure. It's simply guys (there are no women post-rockers, as far as I know) experimenting with the possibilities of their instruments and the limits of their talents.

In this regard, it was an education to see the quartet OlO make its Japan debut at Aoyama CAY March 10. Hailing from the college town of Bloomington, Ind., OlO is about as anonymous as a band can get and still be presented in Tokyo as an important up-and-coming band from America. Though the show wasn't sold out, the basement club was impressively packed, and the opening "session" included musicians from Rovo and Dub Squad, two respected underground groups in Japan.

As with most post-rock, OlO's music is easy to describe but difficult to pin down. Equal parts lite jazz and '70s pop, with occasional vocals thrown in for color rather than meaning, OlO's songs are basically pieces of ideas that have been polished and then stuck together at random. The guitar and keyboards give the overall sound a tropical flavor (via major 7th and 6th chords), but the skittery rhythms prevent the music from making itself completely at home in your mind's living room.

Like Godspeed You Black Emperor!, another anonymous band that ignores rock's prerogatives while exploring its territory, OlO conceives performance as an audiovisual experience, but the homemade videos that played behind the band at CAY weren't half as ambitious, or scary, as the ones GYBE screened at its Tokyo show last November. In fact, the videos emphasized just how unassuming OlO's music is. Rather than complement the roiling instrumentals, the images often distracted from them.

This lack of overt intensity took on a meaning all its own. It was interesting to watch guitarist Corey Allbritten as he switched between plucking and picking modes because he had to place his pick in his mouth for the former and then grab it quickly when he reverted to the latter. Considering the textures he was after, it was an unavoidable nuisance, but it was also something that he had worked out, perhaps painstakingly, so that he could pull it off effortlessly in concert.

The wallpaper analogy was apt to a certain degree: The craftsmanship of the grooveless tunes and the workmanlike playing combined to make OlO's music decorative rather than evocative. Which isn't to say there wasn't real feeling coming from the stage -- or humor. OlO's very name, which in print looks decidedly digital and thus doubly anonymous, provides the group with a nifty solution to titling songs that don't really need titles (the two Japan-only bonus tracks on their second album are "lolo" and "loll").

One could sense a genuine mood of appreciation in the audience, whose members acted as if they were being treated to something that they would never hear again. The beauty of a solo or a particularly clever ensemble riff seemed to emerge from nowhere. It was surprising without being odd or jarring. Discovery was in the air. As the band played the last chords of its last song, a gauzy curtain closed in front of them on the stage. "Thank you, Japan," said the keyboardist. Thank you, too, I thought, whoever you are.