In 1891 Royal Worcester introduced a new system of date coding by changing the shape of the crown and adding the word "England" to the backstamp.
For the next 12 years a dot was added each year first to the left of the crown and alternating until in 1903 there were 6 dots either side of the crown.
Above shows a backstamp for the year 1912
(6 dots either side of the crown =1903, plus 9 dots under the mark)
In 1904 a further series of dots were introduced underneath the circle, again one being added each year until 1915 which would have a total of 24 dots (6 either side of the crown and a further 12 underneath)
Above shows a backstamp for the year 1924
(central star under the mark for 1916, plus 4 dots either side)
In 1916 the system was again changed and the dots were replaced by a single star underneath the circle, and for the next 11 years another dot was added each year alternatively to each side until 1927.
1928 saw another change when the system of dots were replaced with geometric shapes beginning with a rectangle going through to 1933 when dots were added again to either side of the 3 interlocking circles
This system continued for another 9 years from 1933 until 1941
Although the mark had been mainly puce coloured up to this time there were some exceptions eg. blue, green and black.
Above shows a black printed mark from 1935 (3 interlocking circles plus 3 dots)
Between 1942 and 1948 no dating system was used but was re-introduced in 1949 with the letter "v".
1950 saw the letter "W" used, and then each consecutive year a dot was once again added either side of the "W"
This system again continued for a period of 13 years through until 1963 after which no date marks were generally stamped, all backstamps were generally Black from around 1942 onwards, gold backstamps were generally used on acid gold or special pieces.