The BOJ said on Friday it will buy 10 to 100 billion yen ($88 million to 878 million) of JGBs with 25 years or more left to maturity over five occasions in October, versus 50 to 150 billion yen targeted in previous months.

Although such a measure had been expected to a certain extent, some market players were nervous the BOJ may further reduce its bond buying.

The 30-year JGB's yield rose 1.5 basis points to 15-month high of 0.920 percent while the 40-year JGB yield rose 2.5 basis points to 1.090 percent, its highest since late October last year.

The 20-year JGB yield rose 0.5 basis point to 1 1/2-year high of 0.660 percent.

Ten-year JGB futures fell 0.01 point to 150.08 in thin trade of just 17063 lots.

The 10-year JGB yield rose 0.5 basis point to 0.125 percent.

The market showed no reaction to the Bank of Japan's tankan corporate sentiment survey showing the business confidence among at big Japanese manufacturers slipping for three quarters in a row.