The Nikkei 225 index at the Tokyo Stock Exchange added 84.89 points to 8,870.22 by the break.
The Topix index of all first-section issues rose 1.00 percent, or 7.58 points, to 764.98.
The market was underpinned by hopes Greece will strike an agreement with creditors at this weekend's European Union leaders summit, despite an overnight standoff on the troubled country's debt-reduction talks.
A weaker yen against the dollar was seen broadly aiding Japan stocks.
The dollar stood at 77.88 yen at midday in Tokyo, edging up from 77.71 yen in New York Tuesday.
The euro held firm at $1.3029 and 101.47 yen, compared with $1.3030 and 101.25 yen in New York.
"The ground is firming, preparing the market for a further rise later this week," said Okasan Online Securities chief strategist Yoshihiro Ito.
"Large-caps are gaining attention on the backdrop of the weaker yen," he told Dow Jones Newswires.
TDK was up 2.22 percent at 3,675 yen and Sony up 3.09 percent at 1,431 yen.
High-tech firms that supply parts to Apple rose after the iPhone maker reported stellar quarterly earnings results. Murata Manufacturing rose 3.49 percent to 4,295 yen and Toshiba was up 2.07 percent at 345 yen.
Apple said late Tuesday its net profit more than doubled in the October -December quarter to a record $13.06 billion, driven by strong sales of iPhones, iPads and Macintosh computers.
The Dow Jones Industrial Average closed down 0.26 percent to finish the session at 12,675.75. The Nasdaq was up 0.09 percent to 2,786.64.