TOKYO, April 23 (Reuters) - Yields on benchmark 10-year Japanese government bonds (JGBs) were unchanged on Friday as investors held their bets ahead of the Bank of Japan’s policy meeting as well as an announcement of details of its bond buying operations next week. *The 10-year JGB yield was flat at 0.065%. *The 20-year JGB yield was unchanged at 0.430%. *The 30-year JGB yield rose 0.5 basis points to 0.635%. *The two-year JGB yield was flat at minus 0.135%. *The five-year yield was flat at minus 0.110%. *The 40-year JGB yield rose 1 basis point to 0.680%. *Benchmark 10-year JGB futures fell 0.03 points to 151.56, with a trading volume of 21,031 lots. (Reporting by Tokyo markets team; Editing by Krishna Chandra Eluri)