Tokyo stocks rose 1.37 percent by the break on Thursday as exporter shares were boosted by a weaker yen with the market shrugging off a weak session on Wall Street.
The Nikkei 225 index added 140.13 points to 10,370.49 in morning trade, while the broader Topix index of all first-section shares was up 1.32 percent, or 11.15 points, at 858.86.
The Nikkei was on track to finish at its highest close since last year's quake-tsunami disaster as a new Japanese government came to power promising to fix the economy.
"The weaker yen should easily offset US stocks' third straight fall," said SMBC Nikko Securities general manager of equities Hiroichi Nishi.
In forex trade, the dollar rose to its highest level in more than two years against the yen as Shinzo Abe was sworn in as prime minister.
Abe -- whose Liberal Democratic Party won a landslide election victory this month -- has repeatedly said he would pressure the Bank of Japan for more easing measures, comments that have helped bring down the value of the yen.
"Some say the market is now overbought, but the trend is your friend, and few are willing to risk going short at the moment," said an equity trading director at a foreign brokerage.
"Japan is now right in the middle of the radar for foreign portfolio managers."
Toyota shares jumped 2.74 percent to 3,935 yen by the break after the automaker said it had agreed to pay about $1.1 billion to settle a class action lawsuit launched by US vehicle owners affected by a series of mass recalls.
US stocks fell Wednesday on uncertainty about whether a deal to avert the fiscal cliff of tax hikes and spending cuts would be reached by the year-end deadline.
The Dow Jones Industrial Average slipped 0.19 percent to 13,114.59.
On currency markets, the dollar was at 85.79 yen, touching its highest levels since September 2010.
The euro fetched 113.56 yen and $1.3234 compared with 113.19 yen and $1.3230.
-- Dow Jones Newswires contributed to this article --