Japan's key Nikkei index plunged 4 per cent Monday as the yen's advance against the US dollar led investors to shed export-oriented stocks. ( dpa )
The Nikkei 225 Stock Average tumbled 545.93 points in morning trading, or 4.01 per cent, to 13,057.09.
The broader Topix index of all first-section issues also plunged 50.97 points, or 3.85 per cent, to 1,273.31.
Tokyo market players dumped stocks across the board, but the yen's advance mainly hurt exporters as a stronger yen makes Japanese products cheaper and erodes earnings of Japanese firms operating abroad.
On currency markets at 9 am (0000 GMT), the dollar traded at 103.05-10 yen, down from Friday's 5 pm quote of 104.33-35 yen.
The euro was quoted at 1.5200-05 dollars, down from Friday's 5 pm quote of 1.5231-33 dollars, and at 156.65-70 yen, down from 158.91-95 yen.