The dollar marked a fresh seven-year high against the yen on Wednesday, which helped lift the Nikkei to a similar record, while oil prices recovered after data showed a drop in U.S. supply.
MSCI's broadest index of Asia-Pacific shares outside Japan edged slightly down, while Japan's Nikkei stock average was up about 0.8 percent after earlier touching its highest level since July 2007.
A pair of surveys showed that China's services sector grew slightly faster in November, though they did not vanquish fears about a softening Chinese economy.
"Downside pressures on the economy still persist," said Qu Hongbin, an economist at HSBC in Hong Kong, adding that he expected further policy easing in coming weeks.
Wall Street
Wall Street posted solid gains on Tuesday, with the Dow Jones industrial average .DJI closing at a record high, boosted by gains in energy shares as investors searched for bargains in the sector.
U.S. crude rose more than 1 percent to $67.67 a barrel in Asian trade, after industry group American Petroleum Institute (API) released data showing U.S. crude stocks fell 6.5 million barrels last week.
Brent crude added 0.9 percent to $71.16. Brent and U.S. crude are down more than 30 percent since June and touched five-year lows on Monday in recently volatile trade amid massive oversupply.
"The market's volatility is a result of people working out what's going to happen next," said Jonathan Barratt, chief investment officer at Ayers Alliance Securities.
Saudi Arabia would only consider cutting production if other countries, including non-OPEC producer Russia, joined in limits, former Saudi intelligence chief Prince Turki bin Faisal said on Tuesday.