On the second floor of a 2,200-sq.-meter used-goods superstore in the suburbs of Kuala Lumpur, Koji Onazawa pauses beside some old Japanese surfboards. He's spent nearly two decades at Bookoff Corp. — a corporate legend in Japan that's barely known outside it, with 832 secondhand shops across the country. Now he's running Jalan Jalan Japan, the company's first true foray into selling more than just used books abroad. "We're not a representative of Bookoff here," he says. "We're a representative of Japanese secondhand goods."

He's not being melodramatic. According to data supplied by the Japan Re-use Business Journal, more than two dozen Japanese companies have set up at least 62 shops or distributorships selling secondhand Japanese goods in eight Southeast Asian countries in recent years. (Bookoff plans to open four more superstores in Malaysia alone in the next three years.)

Those stores receive much of the nearly $1 billion in used goods that Japanese companies legally exported in 2015 (illegal shipments were at least as large). While Japanese secondhand goods will never overtake new ones in Southeast Asia or elsewhere, they're rapidly growing into a multibillion-dollar industry — and one of Asia's most surprising export growth stories.