TOKYO, July 7 (Reuters) - Japanese government bond yields fell on Wednesday, tracking U.S. treasury yields, as the market witnessed strong results of the Bank of Japan’s bond buying operation. The 10-year JGB yield fell one basis point to 0.030%, and the 20-year JGB yield fell 0.5 basis point to 0.410%. The BOJ said it offered to buy 450 billion yen ($4.07 billion) worth of bonds with a maturity of one-to-three years, and 425 billion yen worth of bonds with a five-to-ten year maturity as well as 30 billion yen worth of floating rate bonds. Yields on the longer maturity were unchanged, with the 30-year JGB yield flat at 0.670% and the 40-year JGB yield was unchanged at 0.740%. The two-year JGB yield was unchanged at minus 0.115%. The five-year yield fell 0.5 basis point to minus 0.115%. Benchmark 10-year JGB futures rose 0.19 point to 152.2, with a trading volume of 24,279 lots. ($1 = 110.6500 yen) (Reporting by Tokyo markets team; Editing by Amy Caren Daniel) Our Standards: The Thomson Reuters Trust Principles.