Watch List notes:

Potosi, Bolivia, cob 8 reales, 1650 O, with crowned-arms (Mastalir Asb) countermark on cross, rare. S-P35; KM-19b; Cal-1488. 28.06 grams. Scarce type with finer-style shield details, as well as an improved castle and corrected spelling of king's name as PHILIPPVS with an I instead of an E, within which this is a rare subtype with modern 5 and dots between digits of date and single large dot after the date (here visible as just 5-dot-0-dot), also rare as non-salvage, with full but slightly doubled shield with clear P-O to left and 8-O to right, nearly full but off-center cross with deeply impressed countermark unusually somewhat removed from the edge, nicely toned VF. Pedigreed to the Roberto Mastalir Collection of Countermarked Potosi Cobs, Plate Coin (page 92 in Part A and page 62 in Part B) in his book The Great Transition at the Potosi Mint, 1649-1653, The 1649-1652 Crowned Shield Coinage and the Countermarks of 1652 (2021).
($400-600)