The Nikkei 225 index at the Tokyo Stock Exchange closed the morning session up 33.96 points at 9,757.20 despite an overnight drop on Wall Street.
The Topix index of all first-section issues rose 0.73 points, or 0.09 percent, to 836.69.
A higher dollar against the yen should provide support for the index Thursday, Nomura Securities senior strategist Juichi Wako told Dow Jones Newswires.
While some profit-taking was likely, Wako expected support for the Nikkei to be firm at around 9,700 for the session.
The dollar was trading at 81.14 yen in Tokyo, edging up from 81.12 yen in New York late Wednesday and around 80.50 yen a day earlier.
The euro bought $1.3337 and 108.20 yen compared with $1.3325 and 108.11 yen in New York.
Among exporters to benefit were Toyota Motor, up 0.59 percent at 3,375 yen, and Sony, up 1.03 percent at 1,755 yen.
Shares in Elpida Memory rose 14.3 percent to eight yen in the morning session after diving 97.2 percent on Wednesday when the Tokyo bourse removed trading restrictions following the microchip maker's bankruptcy filing.
Federal Reserve chairman Ben Bernanke's forecast of continued sluggish growth in the US economy for 2012 sent US stocks lower Wednesday. The Dow Jones Industrial Average fell 0.41 percent to finish at 12,952.07.