Dating delft pottery
If you have a Royal Copenhagen porcelain from this period (1935 to 1984) you can easily identify the exact year the piece was made.From 1935 to 1949 the dot appears above one of the letters of Royal Copenhagen.From 1935 on a green dot was placed over or under one of the letters of the factory name.
This vase bears the makers mark used since 1876: JT (which stands for Joust Theft) with the word Delft underneath; the date code (C. which stands for 1968), the artist's initials (N d G which corresponds to Nico de Graf, an artist who has worked at Royal Delft since 1963 until now) and the style number (825).
Ironically, it is those pieces that do not say Royal (represented by either the word or a crown) which are authentic Royal Delft.
This vase has 18 dots so it must have been made in 1909 (1891 + 18 = 1909).
Royal Copenhagen Siamese Cat Figurine - 1957, Denmark: This porcelain Siamese cat has the Royal Copenhagen mark applied since 1923: a Crown and Royal Copenhagen Denmark in green and three blue wave marks (which represent Denmark's three straits).
If you have a post 1879 Royal Delft porcelain you can identify its age of manufacture by the letters of the alphabet printed on its underside and the following key: 1879 to 1904: A to Z; 1905 to 1930: AA to AZ; 1931 to 1955: BA to BZ; 1956 to 1980: CA to CZ; 1981 to 2006: DA to DZ.