please tell me your nationality,

Depending on the length of stay and nationality, either a tourist or student visa may be required to enter Japan:

Nationals of the following countries may not require visas for stays up to 6 months:
Austria, Germany, Ireland, Liechtenstein, Switzerland, United Kingdom, Mexico

No visa may be required for stays of 90 days or less:
Singapore, Canada, U.S.A., Argentina, Bahamas, Chile, Colombia, Costa Rica, Dominican Rep., El Salvador, Guatemala, Honduras, Suriname, Uruguay, Barbados, Belgium, Croatia, Cyprus, Denmark, Finland, France, Greece, Iceland, Italy, Luxembourg, Macedonia, Malta, Netherlands, Norway, Portugal, San Marino, Slovenia, Spain, Sweden, Andorra, Czech Rep., Estonia, Hungary, Latvia, Lithuania, Monaco, Poland, Australia, New Zealand, Israel, Turkey, Lesotho, Mauritius, Tunisia

14 days or less:
Brunei

Visas are highly recommended for nationals of Malaysia and Peru

Temporarily suspended:
Bangladesh, Pakistan, Iran