The Nikkei 225 Index rose 1.18% to 30,439.54 by 01:44 GMT as financials and real estate shares surged. At one point the Nikkei rose to 30,487.65, the highest since August 1990.
Panasonic was up 1.23 percent at 1,356 yen, while Sumitomo Mitsui Financial was down 0.54 percent at 3,297 yen ahead of their earnings reports due after market close.
Toshiba, which returned to the prestigious first section of the Tokyo Stock Exchange on Friday more than three years after it was demoted to the second section, was trading down 0.87 percent at 3,400 yen.
The number of virus cases continues to soar in Japan and Prime Minister Yoshihide Suga urged people to avoid gatherings, saying "the virus has no holidays".