Tokyo's benchmark Nikkei index closed down 4.41 percent Thursday after the coronavirus outbreak was declared a pandemic and US President Donald Trump announced a ban on travel from Europe.
The Nikkei 225 index lost 856.43 points to close at 18,559.63, while the broader Topix was down 4.13 percent, or 57.24 points, to close at 1,327.88.
Following the World Health Organization's pandemic announcement, "concerns over recession due to a contraction in various economic activities intensified", said Rikiya Takebe, senior strategist at Okasan Online Securities.
The key Nikkei index temporarily lost more than five percent after Trump banned all travel from Europe to the US for a month to fight the coronavirus, ramping up fears the global economy will careen into recession.
"Panic selling continued," said Toshikazu Horiuchi, a broker at IwaiCosmo Securities.
"It's hard to see a short-term bottom of shares now," he told AFP.
The index recovered slightly after Bank of Japan Governor Haruhiko Kuroda held talks with Prime Minister Shinzo Abe and voiced support for financial markets hit by the outbreak.
"We will provide ample liquidity and make appropriate purchases of assets to deal with these economic uncertainties and market movements so that the market and the economy will be stabilised," Kuroda told reporters.