TOKYO, July 2 (Reuters) - Japanese government bond yields fell on Friday after solid demand at a 10-year debt auction in the previous session but investors traded cautiously ahead of key U.S. jobs data. The 10-year JGB yield fell one basis point to 0.040%, while the 20-year JGB yield also eased one basis point to 0.415%. At the longer end, the 30-year JGB yield edged one basis point lower to 0.665%, and the 40-year JGB yield fell 1.5 basis points to 0.735%. At the shorter end, the two-year JGB yield and the five-year yield were both unchanged at minus 0.120% and minus 0.115%, respectively. Benchmark 10-year JGB futures rose 0.08 point to 151.92, with a trading volume of 21,578 lots. Investors are looking to upcoming U.S. payrolls data for any clues on when the Federal Reserve may start to pare back pandemic-era stimulus. (Reporting by Tokyo markets team; Editing by Ana Nicolaci da Costa) Our Standards: The Thomson Reuters Trust Principles.