What is required to visit Japan?
Aside from the two you mentioned...
1.) Small Satchel. Backpacks suck carrying around.
2.) If you have debit or credit cards, call the number on the back and let them know of your plans to travel and when. Super super important
3.) Portable battery charger for your phone (for which you can store in your satchel).
4.) Study up on proper behavior. How to visit a shrine/temple (if you plan on seeing any), how to order food. Don't be a asshole is the key.
5.) Google maps and Google translator will be your best friends.
Otherwise have fun! One thing you will notice is how much English signage there is. It's shocking. So it's easy to get around. Including trains.
To enter Japan as a US citizen you only need a valid passport and a return ticket and you will be issued a 90 day visitors visa.
To have a great memorable experience on your visit you need to plan what you want to do and see.
For only 1 week I would recommend Tokyo and maybe a day trip to the mountains like mount Takao or Kamakura. Coming here for 1 week and using a JR rail pass to cram seeing as much as possible is not recommended. If you had a couple of weeks or a month it makes sense.
Been living here since 1995 and started the first vacation rentals in Tokyo that come with all free advice and assistance for our guests.
Nothing! A ticket in and a ticket out and enough money for your time there. Its good to have an itinerary of what you would like to see and do while there so you will be more organised.
You will love Japan!!! ;) COMMUNITY - ENDLESS WANDERLUSTING - COOL ADVENTURES - EPIC JOURNEYS if you need any travel tips or an itinerary email me and I will help you plan for your trip. I write a lot about Japan on my travel blog as well.
As an American all I needed to show was my passport. A huge recommendation would be a 7 Day Japan Rail pass. This allows you to travel all over using most trains and the rail system is second to none, the first class upgrade grade is worth it, especially if you have bags.
If you're popping in for only seven days, then that falls neatly within ‘tourist visa on arrival'.
Just have your exit ticket information just in case they want to take a peep.