TOKYO, April 22 (Reuters) - Yields on 10-year Japanese government bonds (JGBs) fell on Thursday as some investors remained cautious about the impact of a resurgence of COVID-19, although risk appetite improved overall and stock markets rebounded. * The 10-year JGB yield fell 0.5 basis points to 0.065%. * The 20-year JGB yield was unchanged at 0.430%. * The 30-year JGB yield rose one basis point to 0.635%. * The two-year JGB yield was flat at minus 0.135%. * The five-year yield fell 0.5 basis points to minus 0.110%. * The 40-year JGB yield rose 0.5 basis points to 0.670%. * Benchmark 10-year JGB futures rose 0.04 points to 151.59, with a trading volume of 21,582 lots. (Reporting by Tokyo markets team; Editing by Jan Harvey)