Does Japanese nationality or permanent residency "expire" if you're outside Japan too long?
Permanent Residency can go rotten if unused. One of naturalization's benefits is that it truly is permanent, in that no matter how long you are outside of Japan, it never expires. Contrary to its name, there is nothing that is truly "permanent" about the Status of Residence ( 在留資格 { zairyū shikaku } ; SoR ) known as "PERMANENT RESIDENT" ( 永住者 { eijūsha } ; PR ) or even "SPECIAL PERMANENT RESIDENT" ( 特別永住者 { tokubetu eijūsha } ; SPR ). You do not have to promise, state, or even intend to live in Japan permanently to receive it. On the other hand, if you leave Japan for more than a year without a re-entry permit or you are outside of Japan for a long enough time that your re-entry permit expires, the PR SoR will become invalid. Thus, if a family or work emergency requires you to leave Japan for a long time (years), and it is not possible to occasionally return to Japan to renew the re-entry permit, it is possible to lose one's permanen...