The first step is to identify a group of equipment with technical coherence (assembly, finishing, cooking techniques), functional coherence (crockery, cooking, etc.), and regional coherence, a face, determined by a group of workshops. As it is the result of a response or creation of craftsmen to consumer needs, pottery, while following technical, economic and functional constraints, is not designed as a system, and if we therefore seek coherence, we can always accept exceptions.
The group thus formed must be assigned to one or more categories. Many categories of pottery already exist and we favour the trend towards homogenisation, i.e. in a same language, similar productions are called in the same way. However, there is no question of changing the classes accepted by all. To prevent categories from being classified in alphabetical order, they are given a hierarchical key determined by their function, quality and commercial size. Each category must have a code (TS for samian ware /Terra Sigillata , GLT for Glazed table ware)
The classification of types must seek coherence by shape groups (Plate, Bowl, Bottle, or Plate and Cup) by morphological similarity (more than a numerical or chronological logic).