DECEMBER 31, 2009 Bond Investors Bet on Japan's Day of Reckoning GREGORY ZUCKERMAN AND JOANNA SLATER Some hedge funds are starting to wager on painful times ahead for Japan, the world's second-largest economy. These investors, including some who made successful bets against risky mortgages and financial companies in recent years, anticipate trouble for Japan's financial system. Their concern: Government borrowing continues to climb while demand for the nation's debt could taper off. A collapse of the Japanese government-bond market "is going to happen; it's a question of when," said Kyle Bass, head of Hayman Advisors LP, a Dallas hedge fund,...