What are visa

Well i don't know much about traveling. When i heard about Visa I didn't get it. What are Visa and what do they do for me if I go to Japan?

A visa is a document required to enter a country of which you are not a citizen of. Japan has concluded via waiver agreements with several countries, so that tourists from these countries do not need a visa in order to enter Japan for short term tourist stays.

Straight from the dictionary: An official authorization appended to a passport, permitting entry into and travel within a particular country or region.

A lot of countries have mutual visa exemption programs and if you hold a passport of such a country you don't need a visa. Here is the list of countries that don't need a visa to get inot Japan: http://www.mofa.go.jp/j_info/visit/visa/02.html

I would like to add that the visa and visa exemption programs mentioned above only apply to travel as a visitor, a tourist. If you want to work or study, etc., you'll need to apply for a visa. Where do you apply? You have to apply at the Japanese embassy in the country of residence.