Note: Make sure you check up-to-date government websites when looking for information about visas, or any other legal information.
(Check for the .gov in the website link, or .go in Japan's case). There are many official-looking websites which are not reliable, so please be careful.
Click Here for a list of countries where people do not need a visa to enter Japan, if staying under 90 days.
Note that the period of stay granted at the time of the landing permission will be "15 days" for Brunei, Indonesia, and Thailand.