Tokyo stocks opened 1.72 percent higher on Wednesday after a rebound in US shares and a sharp drop in the yen.
The Nikkei 225 index at the Tokyo Stock Exchange was up 189.78 points at 11,236.70 at the start.
"Global markets continue to normalise, allowing risk-on trading to resume," said SMBC Nikko Securities general manager of equities Hiroichi Nishi.
"This is partially reflected in the fall of the (safe-haven) yen," he told Dow Jones Newswires.
The yen fell after Bank of Japan governor Masaaki Shirakawa offered to step down on March 19, about three weeks before the end of his term, fuelling expectations of further monetary easing in line with Prime Minister Shinzo Abe's policies.
Major Japanese exporters have been raising their earnings outlooks thanks to recent weakness in the yen, heartening investors.
The yen was at 93.55 to the dollar and 127.06 to the euro in early Asian trade on Wednesday, little changed from 93.61 and 127.13 in New York Tuesday afternoon but sharply weaker than 92.28 and 124.67 in Tokyo a day earlier.
The euro fetched $1.3581 against $1.3582 in US trade.
US stocks jumped Tuesday, recovering many of Monday's losses and picking up momentum from solid economic indicators. The Dow Jones Industrial Average finished 0.71 percent higher at 13,979.30.