Bolivia shifted to zinc for this issue after wartime metal requisitioning stripped South American mints of their copper and bronze stocks. The United States' War Production Board effectively dictated base metal availability across the hemisphere from 1942 onward, and several Bolivian denominations were reformulated as a direct consequence. Zinc struck poorly under the conditions at the Casa de Moneda de Potosí, and survivors with fully readable surfaces are less common than mintage figures alone would suggest.
Bolivia shifted to zinc for this issue after wartime metal requisitioning stripped South American mints of their copper and bronze stocks. The United States' War Production Board effectively dictated base metal availability across the hemisphere from 1942 onward, and several Bolivian denominations were reformulated as a direct consequence. Zinc struck poorly under the conditions at the Casa de Moneda de Potosí, and survivors with fully readable surfaces are less common than mintage figures alone would suggest.