The yield of the No. 303, 1.4 percent issue, a key indicator of long- term interest rates, ended interdealer trading up 0.025 percentage point from Friday's close to 1.470 percent, the highest benchmark yield since June 15. It briefly hit a five-month intraday high of 1.475 percent.
The price of the key December futures contract for 10-year bonds lost 0.18 point to 137.38 on the Tokyo Stock Exchange.
Investors were also reluctant to buy the safe-haven asset ahead of auctions for a five-year bond and a 40-year bond this week. Traders said bond selling may accelerate further if the five-year bond auction, which will see an increase in issue volume from this month, ends with poor results.