A. RE-ENTRY PERMIT
Foreign nationals residing in Japan, who wish to leave Japan temporarily and then return during the authorized term of residence, may re-enter Japan without obtaining a visa if they receive in advance a "re-entry permit" from the nearest Regional Immigration Bureau or its branches.
The maximum validity of the re-entry permit is set at "5 years", if it does not exceed the period of stay. In the case of special permanent residents, the maximum validity of the re-enty permit is set at "6 years"
Two types of Re-entry permit are: Multiple which can be used several times within the period of validity and SIngle which is valid for only one time and has to be re-applied once used at the Regional Immigration Bureau.
B. Cases that can and cannot apply for extension of period of validity
Application for extension of re-entry permit within the validity period of the existing re-entry permit. In principle, if the period of validity of the permit has expired, it cannot be extended. If you leave the country on a special re-entry permit, the period of validity cannot be extended.