4 Reales - Carlos IV bust of Carlos IV

Chile's colonial mint at Santiago operated under the supervision of the viceroyalty of Peru, and the transition from the Carlos III to Carlos IV bust on these coins was administratively slow — the new portrait wasn't adopted uniformly across all Spanish colonial mints in the same year, creating a brief overlap period that collectors use to date transitional issues precisely. Santiago was one of the later mints to make the switch.

The .896 fineness was set by the 1728 monetary ordinance that standardized silver content across all American mints, and it held without revision through the entire colonial period. Santiago's assayer marks on these pieces remain the primary tool for attributing individual strikes to specific years within the long run.