Tokyo's key Nikkei index opened down more than three percent Thursday on profit-taking after surging in recent sessions, although US stimulus plans offset worries over the coronavirus pandemic.
The Nikkei 225 index dropped 3.13 percent, or 611.27 points, to 18,935.36 in early trade, while the broader Topix index was down 2.64 percent, or 37.61 points, at 1,387.01.
"Japanese shares are seen dominated by profit-taking sales following rallies in recent sessions," said Okasan Online Securities.
"The rise in US shares on the Trump administration's two-trillion-dollar stimulus is a positive factor, but the Nikkei 225 this week has soared at a rapid pace."
"These recent rallies are seen as a short-term buyback, and investors will take a cautious attitude over the longer term," it added, noting there was little sign the spread of the new coronavirus was slowing.
The dollar fetched 110.48 yen in early Asian trade, against 111.20 yen in New York.
In Tokyo, shares were lower across the board with market heavyweight Fast Retailing dropping 6.34 percent 47,240 yen, and SoftBank Group diving 6.93 percent to 3,881 yen after sharp rallies in recent days on a stock buy-back scheme.
Mega bank Mitsubishi UFJ Financial was down 5.51 percent at 442.2 yen, real estate firm Mitsui Fudosan was off 3.00 percent at 1,877 yen, and pharmaceutical business Daiichi Sankyo was 4.24 percent lower at 6,918 yen.
On Wall Street, the Dow ended up 2.4 percent at 21,200.55.