Tokyo stocks opened 0.45 percent higher on Thursday as the yen's drop against other currencies offset negative sentiment over an overnight plunge in New York shares.
The Nikkei 225 index at the Tokyo Stock Exchange was up 39.09 points at 8,703.82 at the start.
The weaker yen should outweigh sharp weakness shown in overseas bourses on the back of rekindled jitters over the US "fiscal cliff" of spending cuts and tax hikes at year-end and the stalled negotiations to solve it, brokers said.
"The yen's sudden break, combined with fundamentally cheap Japan share valuations should allow the market to edge up initially, and then stabilise by the afternoon," said Hiroichi Nishi, general manager of equities at SMBC Nikko Securities.
A persistently high yen in recent times has made manufacturers' products less competitive overseas.
The euro bought $1.2730 and 102.11 yen in early Asian trade compared with $1.2734 and 102.19 yen in New York late Wednesday. The dollar was at 80.20 yen against 80.23 yen.
The Dow Jones Industrial Average tumbled 1.45 percent to 12,570.95, its lowest close since June 26, as President Barack Obama challenged Republicans to accept tax increases for the wealthy in a deal to avert the fiscal cliff.