 Whereas the Federal Republic introduced a system with space left for the East German postal system after a possible reunification, such as by omitting all codes starting with '1' (except 1000 for West Berlin) and '9', the German Democratic Republic had a system that used all codes starting from '1' to '9' just for East Germany.Today, German postal codes are numeric, consisting of five digits since 1993.Between 1990 and 1993 the old four-digit codes in the former West were prefixed with the letter "W", and in the former East with the letter "O" (for "Ost", which means "east" in German).