Japanese stocks on Wednesday saw their biggest gain in almost seven years, after Prime Minister Shinzo Abe promised to cut corporate tax rates.
The benchmark Nikkei index closed the day up a stunning 7.7 percent. That was the highest one-day spike since October 2008.
Stocks elsewhere in Asia also surged. Hong Kong's Hang Seng jumped 4 percent. South Korea's Kospi added 2.8 percent. The Shanghai Composite Index gained 2.3 percent.
Investors appeared to be encouraged by Prime Minister Abe's statement pledging next year to cut Japan's corporate tax rates, which rank among the world's highest.
Asian stocks were also following the lead of Wall Street, which on Tuesday posted its second-biggest gains for the year.
Global stock markets have fluctuated wildly in the past several months, amid concerns over a slowdown in China's economy, the world's second-largest.
The Shanghai Composite Index has tumbled 40 percent since June, prompting Beijing to intervene to prop up the market.
Beijing has spent $236 billion trying to support the plunging stock market in the past three months, according to an analysis this week by Goldman Sachs.
The strategy has largely stopped the free-fall, but many analysts worry the strategy could also be counterproductive in the long run.