The rarity scale
Radushev and Zhekov grade each coin type by how many specimens are known to numismatics. The scale runs opposite to intuition: R1 is the commonest grade, R10 the rarest — a type of which fewer than five pieces survive, which the authors treat as unique and as a cultural monument of national significance.
| Grade | Known specimens | Types here |
|---|---|---|
| R1 | over 10,000 known | 2 |
| R2 | over 5,000 known | 3 |
| R3 | over 2,500 known | 3 |
| R4 | over 1,300 known | 2 |
| R5 | over 600 known | 4 |
| R6 | between 200 and 600 known | 4 |
| R7 | between 70 and 200 known | 14 |
| R8 | between 15 and 70 known | 13 |
| R9 | between 5 and 15 known | 17 |
| R10 | fewer than 5 known — regarded as unique | 13 |
Coin photographs and reconstruction drawings from A. Radushev & G. Zhekov, Catalogue of Bulgarian Medieval Coins IX–XV c. (Agató, 1999).