The benchmark Nikkei-225 index of the Tokyo Stock Exchange rose 123.55 points to 8,763.16 by noon. The broader Topix index of all first-section issues increased 10.57 points or 1.42 percent to 752.81.
Tokyo stocks gained support from the outset after US markets rose for the third straight day on Wednesday following an upbeat report on durable goods orders, brokers said.
"The three-day advance in US stocks is prompting bargain-hunting and short-covering," said Kazuhiro Takahashi, general manager of investment strategy and research at Daiwa Securities in Japan, told Dow Jones Newswires.
The Nikkei further expanded its gain as investors welcomed the stability of the yen against major currencies. The dollar fetched 76.92 yen Thursday morning against 76.97 yen in New York late Wednesday.
Finance Minister Yoshihiko Noda on Wednesday announced a $100 billion facility aimed at helping companies deal with the strong yen after it last week hit a post-war high against the dollar on global economic fears.
Japan's exporters and automakers got a boost from the weaker yen, with Sony adding 1.87 percent to end the morning session at 1,578 yen and Toyota Motor climbing 1.25 percent to 2,752 yen.
Many Apple-reliant shares rose despite the resignation of its iconic CEO and the company's stock falling more than five percent in after-hours trade in the United States.
"With Jobs' long history of illness, the succession process is probably well-mapped out and his DNA is ingrained in the company," said Hideyuki Ishiguro, strategist at Okasan Securities.
"Nonetheless we may see short-term selling in companies reliant on Apple's future success."
Softbank, Japan's only Apple distributor, rose 0.64 percent to 2,481 yen in choppy trade, while among parts-suppliers, Sharp advanced 1.88 percent to 594 yen and Ibiden added 1.72 percent to 1,768 yen.
Some market participants were on the sidelines ahead of a speech by Federal Reserve chairman Ben Bernanke on Friday, which will be closely watched for signs of whether he endorses a further loosening of monetary policy to boost the sluggish US economy.
Copyright AFP (Agence France-Presse), 2011