Japan's key stock index, the Nikkei 225 index, finished at 50,212.27, closing down 2.5 percent on Wednesday,
The index plunged 1,284.93 points from Tuesday, after losing more than 2,400 points in the morning.
Among the 33 industry sectors in the Nikkei, the machinery and telecommunications sectors saw significant declines.
Analysts said the main reason for the decline was the drag from the U.S. stock market.
"I think it's a real shame. The market had already risen above 50,000 points. I thought it would continue to rise. The fluctuations were drastic. It would be great if it could stay at a high level," said a stock trader in Tokyo.
Meanwhile, the Korean won closed at 1,449.4 won to the U.S. dollar in Seoul's foreign exchange market yesterday, a drop of 0.79 percent, reaching a new closing low in nearly seven months.
Similar to the Japanese stock market, Republic of Korea (ROK)'s market also fluctuated and weakened throughout the day on Wednesday.
The Korea Composite Stock Price Index (KOSPI) sank 2.85 percent to 4,004.42 on Wednesday, with more than 90 percent of sectors closed lower.
The won-dollar exchange rate in the Seoul foreign exchange market closed at 1,449.4 Korean won on Wednesday, falling by 0.79 percent and hitting a record low in nearly seven months.
Japan, ROK stocks slump on Wednesday
Japan, ROK stocks slump on Wednesday
