By Agence France-Presse
The benchmark Nikkei index fell 3.19 percent, or 698.26 points, to 21,192.60 in early trade, while the broader Topix index was down 3.05 percent, or 53.88 points, at 1,711.81.
"Investors are discouraged by a higher yen and plunges in European and US stocks," Yoshihiro Ito, chief strategist at Okasan Online Securities, said in a commentary.
But Kyoko Amemiya, senior market advisor at SBI Securities, said the drops presented an opportunity for investors.
"Falls in Japanese shares certainly reflect drops in US shares, but there is no fundamental change in Japanese corporate performances," she told AFP.
"That means there is now a chance to buy on dips in companies with brisk earnings."
The dollar fetched 108.59 yen in early Asian trade, down from 108.74 in New York and from 109.61 yen in Tokyo Thursday.
Overnight on Thursday, the three major US indices plunged, with the Dow Jones Industrial Average plummeting 4.2 percent to 23,860.46.
The broad-based S&P 500 sank 3.8 percent and the tech-rich Nasdaq Composite Index dived 3.9 percent.
In Tokyo, Nissan dropped 4.85 percent to 1,107 yen after the Japanese car giant slashed its forecast for full-year operating profit.
Its rival Toyota was down 2.79 percent at 7,340 yen.