The Japanese yen fell to its lowest level against the US dollar in seven months, a respite for worries over the strong yen hurting exports and the economy.
Part of the reason for the fall is the Bank of Japan's surprise increase of its stimulus measures.
The yen has fallen by 3.7% against the greenback since the 14 February move.
A strong yen has hurt profit outlooks for Japanese manufacturers, with some focussing on overseas production.
Other firms had used to strong yen to go on buying sprees overseas.
The dollar stood at 80.30 yen on Thursday, having risen to 80.406 overnight - its highest since July.
The Bank of Japan (BOJ) expand its asset purchase programme by 10tn yen ($130bn; £83bn) in an effort to boost growth.
Honda factory in Japan A strong yen makes exports such as cars more expensive overseas, and therefore less competitive
The BOJ also left the cost of borrowing unchanged at between zero and 0.1%.
The BBC's Tokyo correspondent Roland Buerk says another factor is the strengthening of the US dollar, after better than expected economic data out the US.
But he says the yen's decline may not alleviate the troubles of Japanese businesses just yet.
"Back in 2007 the yen was at 117 to the dollar not 80 like it is today, so while some depreciation like this is welcome it probably doesn't go far enough for exporters."
Carmakers, such as Toyota, Honda and Mitsubishi, have been some of the worst hit by the strong yen as it makes their products less competitive abroad.