Japan is part of Asia with capital at Tokyo. American Samoa (American) citizens don't need visa for travelling to Japan as tourist. The maximum duration of stay is 90 days. You can also find useful tips from fellow travellers.
Visa requirements for American Samoa
Visa not required
The period of stay granted at the time of the landing permission will be "15 days" for Brunei, Indonesia, and Thailand, and "30 days" for United Arab Emirates and "90 days" for other countries and regions.