Postal codes in Germany, Postleitzahl (plural Postleitzahlen, abbreviated to PLZ), consist of five digits, which indicate the wider area (first two digits), and the postal district (last three digits).The present system was introduced on 1 July 1993. Before reunification, both the Federal Republic of Germany (FRG) and the German Democratic Republic (DDR) used four-digit codes.Under a transitional arrangement following reunification, between 1989 and 1993 postal codes in the west were prefixed with 'W', e.g.: W-1000 Berlin 30 (postal districts in western cities were separate from the postal code) and those in the east with 'O' (for Ost), e.g.: O-1xxx Berlin.Large users or Großkunden have their own postal codes, separate from those used for postal districts or PO Box number ranges.Postal regions do not necessarily follow state borders, so sorting by state is not practical.