This became stricter with a big reform in 1999 and then further changes. Till then (West) Germany had quite inflspecific wordi g. The constitution says "German

This became stricter with a big reform in 1999 and then further changes. Till then (West) Germany had quite inflspecific wordi g. The constitution says "German citizen is, who is German" and they kept the old Empire's citizen law to have continuity. That's one of the reasons why reunification between East and West bad go be done so quickly (from falling Wall No. 9th 1989 to reunification October 3rd 1990) as East Germans could migrate to West easily as soon as the Wall fell and promise of quick unification was a key promise to prevent even bigger migration.