The followings are control measures against infectious diseases including the COVID-19 which are recommended by the Japan Tourism Agency. (As of April, 2023)
(1) New Travel Etiquette for Visitors
Please plan your trip during less crowded times.
Please refrain from traveling when you feel unwell.
Please practice preventive measures even if you are vaccinated.
Please check your body temperature and clean your hands at the entrance.
Mask use is recommended for in crowded trains or buses.
(2) Guide for when you are feeling ill.
When you need to receive medical care in Japan, you had better look at this site.
(https://www.jnto.go.jp/emergency/eng/mi_guide.html)
Please add this URL to your bookmarks to use in the event of an emergency.
(Reference)
These are based on the recommendations by the Japan Tourism Agency of the Japanese Government.