Japan's main stock index has fallen to its lowest close in 17 months after the strong yen and record-high oil prices worried investors.
Exporters including Sony and carmakers such as Nissan performed badly on concerns about the health of the US economy - a big market for Japan.
The Nikkei closed down 616.37 points, or 4.03%, at 14,691.41.
The frenetic trading session followed a week-long holiday for Japanese financial markets.
"High-flying blue chip exporters are going to have a tough time coping with rising commodity prices, a stronger yen and a slowing U.S. economy," said Masanaga Kono, strategist at Societe Generale Asset Management.
Yen weighs
The yen is trading close to a five-week high while weak US manufacturing data raised fears over the well-being of the world's largest economy.
Crude oil topped $100 a barrel for the first time on Wednesday, threatening the Japanese economy which is reliant on energy imports.
Japanese stock markets re-opened for a half-day session after being close since Friday for the new year break. Full-day trading resumes on Monday.
Among individual shares, Nissan slid 9.2% to 1,117 yen while Mazda Motor dropped 7.7% to 515 yen.
Sony fell 6.6% to 5,790 yen and Canon Inc slipped 5% to 4,940 yen.
BBC News
