125 Réis - João IV Countermarked 1 Tostão

Following Portugal's restoration of independence from Spain in 1640, the new Braganza regime faced chronic silver shortages in Brazil and lacked the infrastructure to strike fresh colonial coinage quickly. The solution was brutal in its pragmatism: existing Spanish colonial reales and worn Portuguese tostões were countermarked and revalued, forcing currency into circulation by royal decree rather than by minting it. João IV's 1663 countermark program was among several such emergency measures applied to whatever silver was already in Brazilian hands.

The wide weight range on surviving examples reflects exactly this — the host coins are not uniform, and authentication hinges on the countermark punch itself rather than the planchet.