Tokyo stocks climbed more than two percent in opening trade on Wednesday, following gains on Wall Street and as official data showed Japan's exports soared in May on a weaker yen.
The benchmark Nikkei 225 index jumped 289.34 points, or 2.22 percent, to 13,296.62 in early trade.
A weaker yen and the rise in US shares would help support the Tokyo market, said Hiroichi Nishi, general manager of equities at SMBC Nikko Securities, tipping exporters to lead the session.
"Technical analysis indicates the Nikkei is in a 'buy zone' and cheaper valuations are attracting foreign investors again," Nishi said.
Japan's latest economic data showed the country's trade deficit widened last month as the weak yen pushed up import costs.
But exports jumped 10.1 percent from the same month a year earlier as the cheaper currency helped make Japanese exporters more competitive overseas.
The data comes as Japanese Prime Minister Shinzo Abe works to stimulate the economy with a growth plan dubbed "Abenomics".
"It is not just the weaker yen increasing the value of exports, the amount of exports is increasing as well," Junko Nishioka, chief economist at RBS Securities Japan, told Dow Jones Newswires.
"This shows Japanese companies are increasingly in better shape... Their profitability is also rising these days, meaning they are becoming more resilient to potential external shocks," she added.
Naoya Nishimura, strategist at Resona Bank, said: "Even though exporters are being bought back, their rise may be capped as players are also staying on the sidelines ahead of the US Fed's policy decision".
Markets have been speculating about when the Fed, which wraps up a policy meeting later in the day, would start tapering off its $85 billion-a-month bond-buying programme, credited with helping buoy global equity markets.
The Dow Jones Industrial Average climbed 0.91 percent to 15,318.23 on Tuesday.
In Tokyo, SoftBank shares jumped 4.58 percent to 5,480 yen after a rival bidder for Sprint Nextel dropped its takeover offer.
US satellite television provider Dish Network said it had cancelled plans to submit a revised bid for the US-based wireless carrier.
SoftBank has offered to pay about $21.6 billion for the company, in what could be one of the biggest foreign acquisitions by a Japanese firm.
In currency markets, the dollar fetched 95.52 yen in early Asian trade against 95.37 yen in New York late Tuesday.
The euro fetched $1.3394 and 127.94 yen compared with $1.3396 and 127.76 yen.