Tokyo stocks opened 1.06 percent higher on Monday, boosted by sharp gains on Wall Street last week and the yen's continued slide.
The benchmark Nikkei 225 index at the Tokyo Stock Exchange was up 99.26 points to 9,466.06 at the start.
"Stock investing conditions continue to improve, while the jump in the euro should provide an extra incentive," Hiroichi Nishi, general manager of equities at SMBC Nikko Securities, told Dow Jones Newswires.
US stocks rallied Friday on signs that the holiday shopping season was off to a good start, with the Dow Jones Industrial Average closing up 1.35 percent at 13,009.68.
Retail behemoth Walmart called it the "best ever" Black Friday, the traditional discount sales day that kicks off the holiday shopping season.
The yen stayed weak against the dollar and euro in currency markets, giving relief to Japanese exporters.
The euro, which hit a three-week high against the dollar Friday on improved German business confidence data and hopes for a key aid payment to debt-wracked Greece, bought $1.2966 early Monday against $1.2973 in New York late Friday.
Against the Japanese currency the euro rose to 107.04 yen from 106.90 yen in US trade, and the dollar was up to 82.54 yen from 82.40 yen.