Wedgwood Jasper Ware – dating from the backstamps
ByI have introduced Wedgwood Jasper ware in previous posts. Todays blog is about telling how old your piece of Wedgwood Jasper from the marks impressed on the base. Wiki has the following entry which is in line with my thinking:
Before 1860: Mark is “Wedgwood”. Usually accompanied by other potter markings and a single letter.
After 1860: A three-letter mark represents in order, the month, the potter, and the year. The year code starts mid-alphabet with the letter “O” for 1860, the letter “P” for 1861, etc., returning to “A” after “Z”. For certain letters there are two possible year dates.
1891-1908: Marks are “Wedgwood”, “England”, separated.
1908-1969: Marks are “Wedgwood”, “Made in England”, separated, or “Wedgwood England” on small objects like thimbles.
1970-present: Mark is “Wedgwood Made in England” as single stamp
In addition to these marks I find that pieces which date fromthe 20th century often have a 2 digit number which I believe is the year which should be prefixed by 19 eg “56″ is 1956. Sometimes you are lucky enough to find pieces which commemorate specific dates and events which helps us date silmilar items from that time.

Hi
Most of the designs were used for many ( 100s) of years on Wedgwood Jasper and so design alone is not helpful for dating them.
There are a few designs which have drifted in and out of fashion or were just used to commemorate specific events. Sorry but I am not expert enough to tell more