TOKYO Aug 25 (Reuters) - Japanese government bond prices were steady to slightly firmer on Monday, with the yield curve flattening at the longest end, helped by pension funds' month-end buying.
The 10-year cash bond yield stood flat at 0.505 percent while the 20-year yield dipped 0.5 basis point to 1.345 percent and the 30-year yield ticked down 1.0 basis point to 1.640 percent.
Longer maturities drew support from firmness in the U.S. Treasury market, even ahead of a 40-year bond auction planned for Tuesday.
The 10-year JGB futures price rose 0.03 point to 146.10 .
(Reporting by Masatsugu Hisatsune; Editing by Eric Meijer)