Hi. It depends on what you're coming to Japan to do. If you're on vacation then I don't think you need to get visa but please check here http://www.mofa.go.jp/j_info/visit/visa/index.html - the Ministry of Foreign Affairs in Japan. If you're coming to work then yes, I believe you will need to arrange a visa. If in any doubt though please check at the link above or ask at the Japanese Embassy where you live.
heyy, so i'm planning on moving to japan to be with my fiance. he is in the military. i was wondering about the passports and visas and all of that good stuff....could you possibly give me any information i need for all of this...i'm sooooo lost. i know the whole 90 days no visa is required but like...i may go for a little while and return to the states for a little while and ship stuff over there, but if i change my mind then would i be able to do the whole visa at the american embassy...even if i'm on a military base?! uggghhhh!!! HELP!!