Tokyo shares opened 1.23 percent higher on Monday after Prime Minister Shinzo Abe scored a big victory in weekend elections, securing parliamentary stability to push his big-spending economic policy.
The benchmark Nikkei 225 index was up 180.11 points to 14,770.02 at the start.
Voters handed Abe a thumping victory in upper house elections Sunday, which will likely usher in a new period of stability for politically volatile Japan.
The win means both chambers will be under government control, unblocking the bottleneck that has hampered legislation for the last six short-term premiers.
"The election result was about as expected, but the confirmation of the result, combined with an upward-trending dollar should keep the Nikkei well-supported today," said SMBC Nikko Securities general manager of equities Hiroichi Nishi.
The dollar was at 100.07 yen in early Asian trade Monday, down from 100.50 yen in New York Friday afternoon.
The euro bought 131.70 yen and $1.3156, compared with 132.08 yen and $1.3142 in US trade.
US stocks ended mixed Friday after strong earnings from some industrial companies were countered by feeble results from Microsoft and other technology firms.
The Dow Jones Industrial Average finished down a scant 0.03 percent to 15,543.74.
-- Dow Jones Newswires contributed to this article --