20 Centavos

Brazil's shift to stainless steel for this denomination in 1975 came as part of a broader coinage reform driven by chronic metal cost pressures during the military government's so-called "economic miracle" period, which was already decelerating badly by mid-decade. The Casa da Moeda had previously struck the type in nickel-clad steel, and the transition created two catalogue-distinct varieties that are frequently conflated by generalist collectors.

The KM#579.1a designation separates this stainless issue from its predecessor — a distinction that matters more than it appears at face value given overlapping date ranges in dealer stock.