1 Real - Charles III

Charles III's monetary reforms of 1772 spelled the end of the cob-style macuquina coinage that Potosí had produced for over two centuries, replacing it with milled portrait coinage struck on round planchets. The 1 Real issues from this transitional window — running from 1760 until the new machinery was fully operational — represent the final years of a production method dating to the 1570s, when Philip II established the Potosí mint to process the staggering silver output of Cerro Rico.

Potosí's assayers during this period were required to initial each piece, making attributable die study possible in ways that earlier colonial issues rarely allow.