5⁄10 Real

The Banco Nacional de Buenos Aires was chartered in 1826 under Bernardino Rivadavia's reformist government, which collapsed the following year — yet the bank, and its copper fractional coinage, outlasted the administration by several years. These pieces filled a chronic small-change void in the Río de la Plata region, where silver coinage had been disrupted by a decade of independence wars and the ongoing conflict with Brazil over the Banda Oriental.

The four CJ varieties reflect successive die changes across the emission period, a detail that rewards attribution work on surviving examples.