8 Reales - Philip V

Potosí's cob coinage — the so-called "macuquinas" — was at the center of one of colonial Spanish America's most damaging mint scandals. Between roughly 1649 and 1652, assayers at Potosí were systematically issuing underweight and debased silver, a fraud that reached the Spanish crown and resulted in executions, the destruction of dies, and a recall of coins across the empire. Philip V's reforms of the early eighteenth century were partly a long institutional response to that crisis, tightening assay controls and pushing toward the milled coinage that would eventually replace cobs entirely by 1773.

The "R" in KM#R31 denotes the royal presentation strikes — specially selected planchets struck for dispatch to Madrid as muestras, official samples sent to the crown to certify that the mint was operating to standard.