Tokyo stocks finished Wednesday's session up 2.13 percent, taking a strong lead from Wall Street where the Dow powered to an all-time high.
The benchmark Nikkei 225 index gained 248.82 points to 11,932.27, its best finish since September 2008, while the Topix index of all first-section shares climbed 1.48 percent, or 14.60 points, to 1,003.22 its highest close since October 2008.
The Nikkei was also given a lift by a surge in under-pressure electronics giant Sharp after reports that its was ready to announce a tie-up with South Korean rival Samsung worth more than $100 million.
"Monetary easing measures by Japan, the US and Europe are providing excess liquidity in the market. The Dow's gains are just part of it," Mitsushige Akino, chief fund manager at Ichiyoshi Investment Management, said.
The Dow has more than doubled its value since March 2009, ending at 14,253.77, nearly 90 points above its former closing high on October 9, 2007.
The record comes as the broader economy continues to struggle to recover from the financial crisis while lawmakers in Washington fight a bitter and debilitating battle over how to trim its massive deficit.
"Risk tolerance is improving," said Hideyuki Ishiguro, senior strategist of investment strategy at Okasan Securities.
"The yen's weakening momentum has eased but expectations for Japan's policy steps are spreading like an undercurrent," he told Dow Jones Newswires.
Last week Tokyo nominated a new leadership team for the Bank of Japan which is widely expected to adopt aggressive easing measures to kickstart the economy.
In Tokyo trading, Sharp ended 14.04 percent higher at 341 yen, after media reports of a huge tie-up with South Korean giant Samsung. The firm had soared more than 17 percent at one point.
After the stock market closed Sharp confirmed it had agreed a $111 million tie-up deal with Samsung that will see the South Korean firm take a three percent stake.
Toyota added 2.01 percent to 4,830 yen, Panasonic rose 1.66 percent to 672 yen and Sony was up 2.60 percent to 1,462 yen while Japan's biggest bank Mitsubishi UFJ Financial Group added 1.52 percent to 535 yen.
In afternoon forex trade, the dollar weakened to 93.15 yen from 93.35 yen late Tuesday in New York, while the euro was nearly unchanged from New York at 121.73 yen.