The Nikkei index at the Tokyo Stock Exchange opened up 18.70 points at 8,440.96.
The Nikkei was likely to edge higher, tracking gains in Europe and the United States, said Chibagin Asset Management strategist Yoshihiro Okumura.
"The sense of relief in overseas markets, as well as hope for more policy easing in China, should provide a bit of a tailwind for Japanese stocks," he told Dow Jones Newswires.
European stocks rallied Tuesday and the euro rose against the dollar as Chinese data and upbeat US company results overshadowed fears over the stubborn eurozone debt crisis.
Ratings agency Fitch also said Tuesday it was not planning to strip France of its top triple-A rating for 2012 while Italy was the most worrying of the embattled eurozone countries and could see its credit rating cut this month.
US stocks closed at their highest level since July on Tuesday after an upbeat start to the corporate earnings season. The Dow Jones Industrial Average finished 0.56 per cent higher at 12,462.47.
The euro edged down to $1.2751 and 98.02 yen in early Asian trade Wednesday from $1.2775 and 98.15 yen in New York late Tuesday. The dollar was at 76.87 yen against 76.80 in New York.
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