20 Centavos

Peru's shift to copper-nickel for this denomination in 1918 came after silver shortages during World War I disrupted the supply of the 900-fine silver alloy previously used for fractional coinage. The country was not a belligerent, but global silver demand — driven heavily by Indian currency requirements under British wartime procurement — pushed raw material costs beyond practical minting thresholds.

The series ran through 1941, by which point wartime pressures were again reshaping South American monetary metals policy.