Tokyo - Japan's key Nikkei 225 Stock Average fell below the 8,000 line on Thursday on concerns over the US economy.
The Nikkei index tumbled 357.59 points, or 4.32 per cent, to 7,915.63.
The broader Topix index of all first-section issues also lost 31.55 points, or 3.81 per cent, to 795.88.
On currency markets at 9 am (0000 GMT), the dollar was quoted at 95.92-97 yen, down from Wednesday's 5 pm quote of 96.73-75 yen.