Benchmark 10-year JGB futures rose 0.26 point to 152.59, climbing to their highest since early December.
The yield on the benchmark 10-year cash JGBs dropped 2 basis points to minus 0.045pc, having briefly hit an eight-week low of minus 0.05pc.
The yield curve flattened as long-dated bonds with positive yields drew more bids, with the 20-year JGB yield falling 3 basis points to a two-month low of 0.235pc.
The 30-year JGB yield fell 3.5 basis points to 0.370pc, a trough last seen on Nov. 5.
The current 40-year JGBs were untraded by mid-afternoon, ahead of an auction of 400 billion yen 40-year JGBs on Tuesday.