In the early '80s, Masayoshi Son only half-jokingly had to "pledge his life as collateral" to skeptical Japanese bankers to get start-up financing for Softbank Corp. Back then, Softbank was an obscure software distributor, and Son was an ethnic Korean with the improbable dream of breaking into Japan's old-boy business culture. Today, Softbank is a $3.7 billion powerhouse. It is Japan's biggest software distributor, an innovative purveyor of Internet services, and a player in satellite TV. Son is one of Japan's richest businessmen, with over $1 billion, yet he strives for more than just wealth. He wants to "become the top global player in digital information services."

He isn't quite there yet. But it's hard not to admire Son's ambition and drive, somewhat softened by youthful looks and a quiet voice that are a bit deceiving. His early experiences with racism in Japan have left a "darkness inside," he says, and he disdains the old-boy network in Japan that wasn't particularly helpful to a young Korean. He regularly criticizes Japan's consensus-driven management and aversion to tie-ups with foreigners. And Son can be demanding, holding twice-yearly, grueling meetings with top executives to scrutinize their business plans.

Son clearly isn't worried about risk. During the past two years, Softbank has spent $4.5 billion on an acquisition spree and taken equity stakes in scores of Internet companies, including Yahoo! He also shocked the cloistered Japanese media world by teaming up with Rupert Murdoch's News Corp. to launch a satellite-TV service. As a result, far-right groups branded Son a traitor, and last year protested at Softbank headquarters. "They're nuts," he shrugs.

Son likes to say he has a 300-year business plan for Softbank. At 40, he just might have time to see many of his ideas through. And in pursuing them, he may end up an agent of change for Japan itself.

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