Japanese record-shop owners head to a San Francisco LP fair to find music that may be considered passe' in the U.S., but is highly sought in Japan. Paula Abdul, Debbie Gibson, and Spandau Ballet are some of the artists who vinyl and CD collectors are looking for. WSJ's Neil Shah reports from San Francisco.

SAN FRANCISCO—Before dawn on a recent Sunday, Dan Oppermann stormed into a record fair, escorting an older Japanese man who had flown from Tokyo on a mission: to buy 5,000 records in one week.

"It's getting tougher," said Mr. Oppermann, 65 years old, a retired government worker. "Everyone is really hustling, trying to find new connections, new sources."

Mr. Oppermann and a small network of fellow collectors host buying trips for Japan's record-shop owners, helping them find old LPs and CDs often considered passé in the U.S.—or simply bad—but that Japan's avid music fans have a yen for.

Photos: A Yen for Vinyl

Record shoppers browse the wares at KUSF Rock N Swap, a 10-hour music-lovers' convention at the University of San Francisco. Eva Roca

This trip's highlight: the KUSF Rock-n-Swap, a 10-hour music-lovers' convention at the University of San Francisco, where Japanese buyers and other vinyl junkies haggled with American record dealers over bargain-bin music while munching on bagels and coffee.

"Our trash is their gold," says Mike Vague, 43, a music dealer who says he has 200,000 records in the climate-controlled garage of his Long Beach, Calif., home.

Consider the prize item in Japanese collector Takeshi "Ima-T" Imaizumi's cache: a promotional copy of the 1986 Rolling Stones record "Dirty Work," considered by guitarist Keith Richards the band's low point. The collector says he paid only $8 for it. "This is very hard to find," he says.

For decades, Japan's record shops have scoured the globe for reco

rds to feed the nation's collectors. Employees of Japanese retailer Disk Union once spent $20,000 in a day at Nashville's The Great Escape record store hunting for tunes including ones treasured by Japan's soft-rock and easy-listening fans. With U.S. record stores closing, this focus on obscure music is making supply difficult to find—and fueling secretive competition.

The U.S. has 1,700 independently owned recorded-music stores, about half as many as in 2003, according to research firm Almighty Music Marketing. The Internet has made music sellers and buyers savvier about prices, eroding dealers' profits. Vinyl is also back in vogue in the U.S., bringing new competitors.

Japan has surpassed the U.S. as the biggest seller of CDs, vinyl and cassette tapes, with 25.4% of global sales, according to the Recording Industry Association of Japan. Tower Records Japan Inc.—which survived its U.S. parent's closing in 2006—opens its 87th store this month.

But demand in Japan for older or niche recordings is also unusually strong.

In Tokyo, Disk Union trading manager Yuji Watase said that his teams are making more trips to the U.S. than in decades—powered by a strong yen that cheapens purchases. But when asked what he buys, he clammed up. "It's a business secret," he said. "You can't hear about it."

In this game, a well-stocked Rolodex means getting first dibs on records instead of rifling through crates once they've been picked over. Osamu Ueno, an independent record buyer, says he moonlights for a Japanese buyer as its eyes and ears in San Francisco—for a 10% finder's fee. Mr. Ueno wouldn't give details, fearing prices of mentioned CDs would rise, but he offered this: "When you find these CD titles, they're usually in the clearance sections for 99 cents."

Much of what the Japanese want goes for higher prices. Collectible artists in Japan include female pop singers like Patti Page, whose "(How Much Is) That Doggie in the Window" was a 1950s hit, and 1980s teen idol Debbie Gibson. A "Doggie" record-single goes for $5 in the U.S. and $30 in Japan, while Ms. Gibson's LPs can fetch $200 on eBay. The Japanese "like sugary sweet pop," collector Alec Palao says.

But some things, like privately pressed novelty records, are "rare for a reason," says Mr. Vague, the Long Beach dealer. "No one wanted them in the first place."

Then there are outré 1970s bands like Yes and Traffic and 1980s heavy-metal heroes Bon Jovi, Iron Maiden and Mr. Big; such albums sold for $10 to $15 at KUSF's fair. As a general yardstick, dealers say records sold in the U.S. usually fetch about three times as much in Japan.

"Sometimes I think, how the hell did you get that?" says Eric Martin, vocalist for Mr. Big, which once released a record shaped like an electric drill that Japan's collectors still prize. (Mr. Big's guitarist Paul Gilbert used a drill to play his instrument on the group's 1991 single, which now costs $13 online.)

A few years ago, Sony Corp.'s Japanese music arm convinced Mr. Martin, a Bay Area local, to sing famous pop ballads by Japanese women. The resulting album, 2008's "Mr. Vocalist," sold around 200,000 copies, turning him into an idol in Japan.

In October, he plans to fly to Tokyo to promote his next record, "Mr. Rock Vocalist." Mr. Martin owes a great debt to Japan, he says, but still smarts when rock-singer friends mention the "Vocalist" moniker. "That's a major teasing factor," he says.

The Japanese fascination with America's musical flotsam is a legacy of Japan's music business, which for years promoted U.S. and European rock bands that never took off or were declining in their own countries—a strategy aimed at avoiding competition with the U.S. music industry. That prompted fan cultures to sprout up around maligned American genres like 1980s pop-metal.

At the same time, Japan's baby boomers grew up hearing American jazz and rock—giving bands like Kiss nostalgia power. Japanese record collecting also is rooted in a national fixation with connoisseurship, says Carolyn Stevens, a professor at Monash University in Australia and author of "Japanese Popular Music."

In a competitive environment, record buyers are discreet. Mr. Oppermann says he escorted his Japanese client on a record-buying tour earlier this month, visiting the homes of collectors in Marin County, Sacramento and San Jose. He wouldn't say what the man bought or from whom. He said the man declined to be interviewed.

Bud Nemier, a San Jose dealer, says an unnamed Japanese buyer bought 200 records from him around that time, mostly easy-listening and 1970s rock. "He hit the Pink Floyds," Mr. Nemier says.

At the record fair in San Francisco, Mr. Oppermann's Japanese friend dug through dusty crates of LPs starting at 5:30 a.m., when dealers were just setting up for the day's "early-bird" session. The man's younger assistant, a bespectacled rock specialist, also combed the crates.

Buyers can be extremely selective, even with albums that cost around $4. "You know how they say in real estate it's all about location, location, location?" says Mr. Oppermann. "Here it's all about condition, condition, condition."

Write to Neil Shah at neil.shah@dowjones.com