TOKYO, July 20 (Reuters) - Japanese government bond prices edged down across all maturities on Monday as investors maintained a cautious stance ahead of a 20-year debt sale.
Benchmark 10-year JGB futures inched down 0.04 point to 152.37, with a trading volume of 13,958 lots, while the 10-year JGB yield added 1 basis point to 0.020%.
Investors stayed in the sidelines ahead of a 20-year JGBs auction due on Tuesday, and the finance ministry is expected to offer 1.2 trillion yen ($11.20 billion).
In the super-long zone, the 20-year JGB yield and the 40-year JGB yield gained 1 basis point each to 0.415% and 0.630%, respectively.
The 30-year JGB yield rose 1.5 basis points to 0.595%.
At the short end of the market, the two-year JGB yield and the five-year yield inched up half-a-basis point each to minus 0.145% and minus 0.120%, respectively.
($1 = 107.1600 yen)
Reporting by Tokyo Markets Team, Editing by Sherry Jacob-Phillips