Japanese billionaire Hiroshi Mikitani decided two years ago that the employees at his company, Rakuten Inc., should work almost entirely in English. The idea, he said, was a daring and drastic attempt to counter Japan's shrinking place in the world.

"Japanese people think it's so difficult to speak English," Mikitani said. "But we need to break the shell."

With the move, which took effect at the beginning of last month, Mikitani turned his e-commerce company - an Amazon competitor - into a test case for corporate Japan's survival strategy.

As Japan's population declines, all but guaranteeing ever-decreasing domestic business, companies here are grappling with how they should interact with the world and whether they can do it successfully.

The country has both a dread of English and an understandable attachment to its own ornate business customs. Those idiosyncrasies made Japan a bewildering but envied powerhouse during its economic boom. They now make Japan a poor match, experts say, for global business.

Mikitani took a step few other companies here have dared because, he said, he thought it would help his company expand and thrive. He also wanted to prove a point - that the Japanese, counter to the stereotype, could embrace the risks and embarrassment that come with learning a foreign language.

At the time of the 2010 announcement, only about 10 percent of Rakuten's 6,000 Japanese employees could function in English, according to a case study by the Harvard Business School.