About the Passport

Does my passport need to be valid for six months upon entry into Japan?
No. Japan will allow entry up until the expiration date of the passport. 

Does the passport have to be signed when applying for the Japan visa?
Yes. The applicants passport must be signed when applying for the Japan visa. The signature on the application must match the signature on the passport.

About the Visa

How far in advance can I apply for a Japan visa?
The furthest in advance you can apply for a Japan visa is 90 days.

When does the Japan visa start?
The start date is based on when the consulate issues the visa, not the travel dates provided on the itinerary. Therefore, the visa is valid from the date of issue at the consulate.