It can also appear on later pieces, but other indications will help to place these pieces in the correct period.
: The name of the factory was added during two periods.
The second period can be easily distinguished as the word : Sometimes added from 1939 until the 1950's. A number of references talk about marks being impressed a letter at a time, and assign early dates on this basis; however marks often look like this because the clay has moved in firing and this is very difficult to determine.
I am also aware of at least one example on which the mark was made up a letter at a time, but which certainly dates from around 1790, so it is dangerous to assign too much meaning to this.
When items were made that were not destined for export, they were sometimes omitted, and other indications will confirm the later date.
The classic example is the Bert Bentley portrait medallions, which often had only ENGLAND, or nothing at all, but were mostly made in the 1920's.
Determining the specific year of production of an item is somewhat more complicated, and this calls for close examination of a variety of other marks, such as three-letter date marks, registration marks, artists signatures or monograms and other devices.
From 1780, ornamental Jasper, Black Basalt, cane, terra cotta and Queens Ware are always marked with this stamp. Size codes are found on some items, particularly tea wares, from about 1870 to 1930.These are always divisible by 6, and represent the number of items that went into the kiln on one tray.These are not date marks and, with a few notable exceptions, have no meaning to us now.A three letter date code is sometimes found and starts in 1860 but is rarely found on jasper or basalt items; it absence is not indicative of any date.