Japanese Version

　Extension period of Dependent visa depends on his/her Supporter’s period. The following criteria are used in principle, which may be however shortened down to 1 year by discretion of Immigration Office.

• When Dependent visa renewal is applied at the same time with Supporter’s visa renewal, then the Dependent’s extension period is set to the same as of the Supporter’s.
• When Dependent visa renewal is applied alone, then the Dependent’s extension period is set to the shortest period, among ones specified for Supporter’s visa, that goes beyond remaining duration of Supporter’s visa.

　Please find more details and an example in this page of web site.

Link: How Immigration Office Assigns Extension Period