No – A visa is not required for travel to Japan if you are a Citizen of the United States of America.
A tourist visa is not required to visit Japan for up to 90 days.
The traveler must be in possession of a passport valid for 6 months beyond stay and a round-trip or onward ticket.
Original, signed passport valid for 6 months beyond stay in Japan, and with at least one blank passport page available for Japanese stamp(s).
Proof of Travel Arrangements:
Confirmed round-trip or onward airline ticket.
Register your trip with the US Embassy:
The US State Department strongly encourages American citizens planning international travel to register with the US Embassy(s) in the countries they plan to visit.