The benchmark Nikkei 225 index ended up 1.83 percent, or 531.78 points, at 29,659.89, while the broader Topix index gained 1.28 percent, or 25.77 points, to 2,041.22
Weaker jobs numbers, due to be released on Friday, could instead cement a case for later action - a pre-announcement in November with a formal decision in December
Thousands of corporations from Toyota Motor to telecom giant SoftBank Group are setting up clinics in a massive private-sector vaccination drive, which will begin on Monday.
Toyo Seikan Group Holdings, up 7.9%, was the largest percentage gainer on the Nikkei, followed by Hino Motors gaining 7.14% and Yaskawa Electric Corp up 6.57%.
In the cryptocurrency market, ethereum spot prices fell 1.21% to $1,595 after the listing of ethereum futures on the Chicago Mercantile Exchange on Sunday.
Shionogi & Co gained 1.12% after the drug maker said it sold the development and marketing rights for a COVID-19 treatment to California-based biotech BioAge Labs Inc.
Chip-testing equipment maker Advantest surged 5.45 percent to 8,710 yen, while chip-making equipment manufacturer Tokyo Electron climbed 5.27 percent to 42,950 yen.
The stocks that gained the most among the top 30 core Topix names were Murata Manufacturing Co Ltd up 4.67%, followed by Daiichi Sankyo Co Ltd gaining 2.64%.
Mitsuo Imaizumi, chief FX strategist at Daiwa Securities in Tokyo, expects the pound and euro to decline against the dollar, reaching $1.30 and $1.15 respectively by the end of the summer.