The benchmark Nikkei 225 index slipped 0.01 percent or 2.41 points to 20,625.60 in early trade, while the broader Topix index added 0.08 percent or 1.13 points to 1,499.19.

Many Tokyo investors were expected to sit on their hands before Fed chair Jerome Powell delivers a highly anticipated speech at the annual Jackson Hole conference of central bankers later in the day.

US President Donald Trump has been openly criticising Powell and demanding the Fed cut rates further to prop up the economy.

A lukewarm performance in US shares overnight also failed to inspire players. The Dow finished up 0.2 percent, while the S&P gave up 0.1 percent.

"The Tokyo market was expected to move within a narrow band. The US market moved little and did not produce fresh incentives," Okasan Online Securities said in a commentary.

"The market is likely to take a wait-and-see attitude ahead of the Jackson Hole meeting and the G7 gathering," Okasan said.

The dollar bought 106.51 yen, a tad higher from 106.42 yen in New York.

Among major shares, SoftBank Group rose 0.13 percent to 4,751 yen. Toyota climbed 0.03 percent to 6,908 yen.

Sony added 1.40 percent to 5,933 yen, Mitsubishi UFJ Financial Group was up 0.26 percent at 501.8 yen.