Requirements for tourism in Japan?

Regarding United states citizens, I am not entirely sure if a tourist visa is a definite requirement. Also i don't know (even though it is obvious) if a hotel or residence is required for a stay of over 24 hours. For instance, constant travel throughout the city of choice.

I am not entirely sure if a tourist visa is a definite requirement.

No, it not. You can enter with your US passport for up to 90 days without a visa.

Also i don't know (even though it is obvious) if a hotel or residence is required for a stay of over 24 hours.

No, it is not.

It's not required to have a place to stay over night?? I assumed since that is what they will be asking . That they wouldn't allow any passage if a Hotel or residence was not acquired.

I have never been asked if I had already rented a hotel room or..when entering Japan (same in the USA, UK and other euro countries, China etc..)

You have to write your "address in Japan" on the immigration card when you arrive. Of course, it is unlikely that they will check whether or not you actually stay at that address.