The five- and 10-year JGB yields were flat at minus 0.175 percent and minus 0.055 percent, respectively.

The 30-year yield dipped 1 basis point to 0.510 percent , aided by investor demand for longer-dated debt which typically emerges at the beginning of each fiscal year.

Japan's domestic fiscal year began on April 1.

JGBs also drew mild support as the Bank of Japan offered to buy 1.23 trillion yen ($11 billion) of one- to 10-year bonds at a regular debt-purchasing operation on Wednesday.

Stock markets in Asia advanced, with Japan's Nikkei rising 0.9 percent, on optimism over US-China trade talks.