Applicants wishing to apply for long term stay visa should obtain a Certificate of Eligibility from an immigration office (see following web-site) located in Japan before applying visa.
http://www.immi-moj.go.jp/english/tetuduki/index.html

・ Application form with applicant’s photo affixed (Form can be downloaded)

・ Certificate of Eligibility

・ Supporting documents for travel expenses

　　- Letter of Guarantee (Please see the attached sample)

　　- Letter of Reason for invitation (Please see the attached sample)

NOTICE:

- The applicant(s) is/are requested to submit visa application at least two weeks　before departure date.

- During the visa process, as required by the Embassy, the guarantor as well as the applicant(s) might be asked to provide additional document(s).