Japan has visa exemption agreements with 61 countries and regions (as of April, 2012). Citizens of these countries who plan to stay in Japan no longer than the period specified in these agreements do not require a visa. Foreign participants should contact the Consular Section of the Embassy or Consulate General of Japan nearest you as soon as possible, to determine their particular visa requirements. Those requiring visas must initiate the application process well in advance of their departure date.
More detailed information how to obtain a Japanese visa is shown at the website below. "Ministry of Foreign Affairs of Japan" http://www.mofa.go.jp/j_info/visit/visa/