The Nikkei 225 stock average tumbled 3.8 percent Monday as investor confidence took a beating amid worries about a potential debt crisis in Hungary and disappointing U.S. employment data, while the yen's strength against the euro hurt exporter shares.
The Nikkei dropped 380.39 points, or 3.84 percent, from Friday to close at 9,520.80, marking the largest one-day fall in terms of percentage since March 30, 2009.
The broader Topix index lost 30.95 points, or 3.48 percent, to end at 859.21.