Bone china is a kind of porcelain that contains bone ash. Its making was first developed in Britain and was borne out of the need to compete with the quality of imported ceramic products from China. Porcelain makers, including bone china producers, mark their works through backstamps, a kind of label placed on the underside of the porcelain piece. Backstamps are primary references for identifying and dating a piece of porcelain.
Anyone who wishes to delve into the world of collectable bone china must first be armed with the basic knowledge of who the manufacturers are. This can be quite daunting because there are numerous makers. But the majority of those who produced bone china deemed collectable are British and that somewhat shortens the list.
Each bone china maker had their own crests or emblems printed on the backstamps. Sometimes, they would include their names, but other times only the use of initials or abbreviations would be found. Some makers, however, did not consistently use the same crest. This is especially true with manufacturers who have been around since the late 18th century, when bone china making started to become popular. Research on a company's history is a wise move before settling on a specific piece.
Certain other words or phrases also are printed on the backstamp. Depending on the terms used, the approximate date of a manufactured piece can be determined. The term "England," for example, means that the piece of china was made no earlier than 1891, as porcelain makers were obliged to include this to comply with the McKinley Tariff Act. Much of the time, approximations might be the closest you will get. For more accurate dating, consulting an antiquarian or directly visiting the manufacturer--if possible--will be more helpful.
Another piece of information often included in backstamps is the registry number. The practice of including these numbers, however, only began in 1884. This number is frequently printed with the abbreviation "Rd." followed by a number. These numbers refer to the year a particular design was registered in a public record office. Makers began implementing this action to prevent duplication of designs. Registry numbers are not to be mistaken for the date of manufacture.
Manufacturers eventually employed their own system of symbols to mark dates of manufacture on the backstamps. Royal Worcester, for example, began placing dots near the crown symbol of their crest in 1891. But in 1903, the placement of the dots was changed and put under the crest. Because the identification system of each maker has, and may, change over time, a bit of digging into the manufacturers' history might be necessary.