Tokyo stocks rose 0.47 percent on Friday as the yen fell further against the dollar and euro.
The benchmark Nikkei 225 index gained 52.68 points to 11,191.34, while the broader Topix index of all first-section shares was up 0.26 percent, or 2.40 points, at 942.65.
Equities also benefited from investment flows at the start of the month, said Hiroichi Nishi, SMBC Nikko Securities general manager of equities.
The stimulus and monetary easing policy of Japan's new government under Prime Minister Shinzo Abe was also driving investor confidence, he told Dow Jones Newswires.
"Aside from the yen, stocks will benefit from new-month investment flows, as well as persistent confidence in 'Abenomics' and the central bank easing theme," he said.
In forex trade the dollar stood at 92.21 yen, from 91.70 yen in New York on Thursday, while the euro rose to 125.88 yen, compared with 124.52 yen.
"The yen's weakening is due more to bullishness for the dollar ahead of tonight's US jobs data," says a director of equity trading at a foreign brokerage.
"Players want to see more data confirming the state of the US economic recovery. Longer-term, the bias on the currency market still favours a continuing move for dollar-yen to the mid-90 yen levels," he told Dow Jones Newswires.
The weaker yen helped exporters, with Toyota advancing 2.97 percent to close at 4,495 yen and Honda rising 0.28 percent to 3,515 yen.
Nomura Holdings was down 2.66 percent at 512 yen, despite saying Thursday its net profit rose 13 percent in the October-December quarter.
Sharp surged 5.78 percent to close at 329 yen. The embattled electronics giant said after markets closed that it had eked out a small operating profit in the October-December quarter, but had a whopping $4.6 billion net loss in the nine months to December.