VISA:
Do you have ICAO ePassport? Please check this site http://www.mofa.go.jp/j_info/visit/visa/short/novisa.html#notice03
If yes, you don't need a visa to visit Japan for short-term stay (less than 15 days).
If not, you need a visa, if it is the case, I will provide you certain documents which you need for obtaining the visa. You also need to prepare some documents by yourself, therefore I suggest you to consult with Japanese Embassy/Consulate in your country.