Based on the New border measures (27) released on February 24, foreign nationals, except for those for tourism purpose, are finally allowed for new entry into Japan under the responsibilities of receiving organizations from March 1, 2022.
It takes a few more steps than usual but if we follow this regulation and proceed step by step, you can enter Japan.
The official government announcements are subject to change.
Also, required procedures such as visa application vary by country and region. Please check this site for the most up-to-date information.
Ministry of Foreign Affairs of Japan: Measures for Resuming Cross-Border Travel