The Tokyo Stock Exchange's benchmark index rose to its highest level this year on Tuesday. Semiconductor-related shares led the gains as investor confidence was boosted by the robust earnings forecasts of many companies.
The Nikkei 225 finished the day at 29,842, up 0.7 percent from Monday's close. It has risen for 4 straight trading days.
The broader TOPIX rose to 2,127, reaching its highest since August 1990.
Foreign investors are driving the recent rally. They have been actively picking up shares of Japanese firms.
Their buying on the TSE's top-tier Prime market outweighed their selling by 2.4 trillion yen, or about 17.7 billion dollars, in the 6 weeks leading up to early May.
The gains are coming as worries about financial turmoil in the United States and Europe have eased somewhat.