On hopes of business recovery, Tokyo's benchmark Nikkei index jumped nearly 2% Monday, closing above the psychologically important 30,000 mark for the first time in more than three decades.
The Nikkei 225 index rose 1.91%, or 564.08 points, to 30,084.15, the highest close since 1990.
The broader Topix index advanced 1.04%, or 20.06 points, to 1,953.94.
"The 30,000 mark is symbolic but it's still a waypoint," said Toshikazu Horiuchi, a broker at IwaiCosmo Securities.
"Market sentiment has been supported by hopes for business recovery ahead of the nation's first vaccination," Horiuchi told Agence France-Presse (AFP).
The coronavirus vaccine rollout is scheduled to start as early as Wednesday in Japan for healthcare professionals.
"Hopes for stimulus and monetary easing are also high, which helped bolster positive sentiment, but profit-taking could emerge at this level as the market is overheating," he added.
Masayuki Kubota, chief strategist at Rakuten Securities, said: "The Nikkei index is climbing as central banks in Japan, the United States and Europe keep their massive monetary easing policies in place because of the pandemic."
Ahead of the opening bell, the government said Japan's economy shrank in 2020 for the first time in more than a decade as it was battered by the coronavirus but the contraction was less than expected.
"The market largely shrugged off the GDP figures, which were already factored in," Horiuchi said.
The dollar fetched 105.02 yen in Asian afternoon trade, against 104.91 yen in New York late Friday.
Investors were paying attention to the impact of a 7.3-magnitude earthquake, which hit northeastern Japan late Friday as news reports said more than 150 people were injured and shinkansen bullet train services were suspended.
"There was a chilling moment after the powerful quake in the Tohoku region this weekend, but the impact on the market seems to be limited," Okasan Online Securities said.
In Tokyo trading, SoftBank Group surged 2.12% to 10,005 yen after releasing strong earnings last week, while Uniqlo casual wear chain operator Fast Retailing jumped 4.09% to 99,460 yen.
Nissan plunged 2.83% to 609.9 yen following a news report that Apple had approached it in recent months about self-driving cars, which did not move forward. Nissan denied it was in talks with the U.S. tech giant.
Toyota rose 0.51% to 8,456 yen with Honda up 1.09% at 3,052 yen.
Online mall giant and mobile carrier Rakuten plunged 6.48% to 1,110 yen after it reported a massive annual loss last week.