1883 Peru 1c Green Overprint with UPU and PERU Triangle

Peru · 1883 · 1c

A 1 centavo green stamp of Peru from 1883, featuring two black overprints: 'UPU' and a 'PERU' triangle.

This stamp reflects Peru's adherence to the Universal Postal Union (UPU), indicated by the 'UPU' overprint, standardizing its postal services for international mail. The 'PERU' triangle overprint likely served as a control or revalidation mark.