TOKYO, Aug 18 (Reuters) - Japanese government bond prices were weaker on Wednesday, though moves were limited with many investors were on the sidelines as they looked to more guidance from the Federal Reserve on its policy and due to lingering concerns about the Delta variant. Benchmark 10-year JGB futures fell 0.06 point to 152.33 while the yield on the benchmark 10-year cash JGBs rose 0.5 basis point to 0.010%. Earlier this month the 10-year JGB yield has fallen to 0% earlier this month but no investor were ready to buy them at negative yields, making traders see the zero percent level as an effective floor. U.S. Federal Reserve Chair Jerome Powell dropped few hints on his thinking of monetary policy in his speech on Tuesday, leaving traders to look to his comments at central bank symposium at Jackson Hole next week. The 20-year JGB yield was flat at 0.395% while the yield on the 30-year JGBs rose 1 basis point to 0.645%. (Editing by Rashmi Aich) Our Standards: The Thomson Reuters Trust Principles.