Tokyo stocks fell 1.06 percent Tuesday morning on the back of a stronger yen and a Wall Street plunge while investors were also spooked by deadly blasts in Boston.
The Nikkei 225 index at the Tokyo Stock Exchange was down 140.16 points at 13,135.50 by the break, while the Topix index of all first-section issues was down 1.84 percent, or 20.83 points, at 1,113.16.
Exporters were hit as the yen climbed. The dollar was changing hands at 97.10 yen in Tokyo, compared with 96.56 yen in New York Monday afternoon and 98.32 yen in Tokyo earlier Monday.
The euro bought 126.67 yen and $1.3042, against 125.98 yen and $1.3048.
"Exporters have been moving in reaction to the yen's value," said Naoki Fujiwara, fund manager at Shinkin Asset Management. But the yen is likely to continue to weaken as long as no developed countries oppose the Bank of Japan's new easing measures at a G20 meeting this weekend, he added.
A slump in US stocks, the dollar's fall and the Boston bombings were all combining to send the market down, said SMBC Nikko Securities general manager of equities Hiroichi Nishi.
On Wall Street the Dow lost 1.79 percent, while the broad-market S&P 500 was down 2.30 percent.
The losses in global equities came as commodities also suffered strong selling pressure, with gold sinking nine percent in New York and oil prices also battered.
At least three people were killed and more than 100 wounded when twin explosions struck near the finish line of the Boston Marathon on Monday.
The incident happened about an hour before the US markets closed.
In Tokyo on Tuesday Toyota Motor was down 1.44 percent at 5,460 yen, while Canon lost 2.04 percent at 3,600 yen.
Softbank dropped 8.85 percent to 4,270 by the break after a US satellite-television provider trumped the Japanese mobile operator's bid to buy Sprint Nextel.
And among financials Nomura Holdings was down 1.66 percent at 766 yen, and Mitsubishi UFJ Financial Group fell 3.46 percent to 640 yen.
-- Dow Jones Newswires contributed to this report --