Japanese government bonds fell Thursday, with 10-year rates touching 1 percent for the first time in a year, on speculation the U.S. Federal Reserve will curb stimulus and the Bank of Japan will tolerate an increase in yields.

Japan's five-year note rate matched the highest in two years after Fed Chairman Ben Bernanke said Wednesday the Fed may trim bond purchases if policymakers see indications of sustained economic growth. The BOJ injected ¥2 trillion into the financial system to stem volatility following a circuit breaker in JGB futures trading.

"It was a kind of shock for bond holders," Genzo Kimura, an investor at Sumitomo Mitsui Trust Asset Management Co., said of Bernanke's comments. "We expected that he was not ready for tapering."