The market immediately reacted to the move, with the 30-year JGB yield falling 10 basis points (bps) to 1.475%, its lowest since Oct. 14.
The BOJ conducted emergency bond buying operations for two straight sessions last week only to see yields keep rising.
Yields on shorter end notes also fell, with the two-year JGB yield retreating 1 bps to -0.025%.
The BOJ offered to buy 350 billion yen ($2.36 billion)of bonds with 10- and 25-year maturities, up from 250 billion yen it had planned.
The BOJ said it would also buy 575 billion yen of bonds with 3- to 5-year maturities, up from a planned 475 billion yen, and 150 billion yen of bonds with maturities more than 25 years, up from 100 billion yen.