Tourist and Business visas are not required for citizens of the United States for a stay up to 90 days. However, your passport must have at least one blank visa page and be valid for six months. If your passport is expiring or you need to have additional pages added you can view the requirements here.
Fast Passports & Visas always recommends checking with your airline as requirements may change without notice.
Japan requires that citizens of foreign countries obtain a visa to enter.  The Japanese Consulate General will determine the duration of stay upon receiving an application.  The types and categories differ according to the purpose of visit, length of stay and respective arrangement with the country of the foreign national.

Tourist: Tourist visas are issued to applicants who are traveling to a foreign country to experience its culture, landmarks, and landscapes, but not to conduct any Business, Technical labor, or take up employment.
Business: Business or Commerce visas are issued to applicants visiting a foreign country for the purpose of meetings, negotiations, and/or presentations, but not to take up employment or to conduct any technical labor.