TOKYO, June 8 (Reuters) - Longer-dated Japanese government bond yields declined on Tuesday following a smooth auction of about 900 billion yen ($8.23 billion) of 30-year debt. The 30-year JGB yield fell 0.5 basis point to 0.685%, after earlier climbing to a more-than-two-month high of 0.695%. Yields on 20-year paper declined 1 basis point to 0.445%. The bid-to-cover ratio rose to 3.39 at Tuesday’s sale, up from 3.12 at the previous tender of 30-year JGBs on May 13. Trading was subdued again like Monday, with five-year securities untraded as of 0525 GMT. The 10-year JGB yield was flat at 0.075%, and the two-year yield was also unchanged at minus 0.125%. Benchmark 10-year JGB futures rose 0.07 point to 151.61, with a trading volume of 26,730 lots. “Since the U.S. nonfarm payrolls report, volatility in U.S. rates has dropped, leading to a heightened sense of stasis in the Japanese bond market,” said Ataru Okumura, a strategist at SMBC Nikko Securities. ($1 = 109.4200 yen) (Reporting by) Our Standards: The Thomson Reuters Trust Principles.