(Photo: VNA)

The stamp’s main color is blue, UPU's color. The number 50 represents 50 years of the UPU international letter writing competition journey, stylized with the UPU logo and a globe with five colors representing five continents.

The design symbolizes children around the world being connected and joining the contest. The stamp background features image of envelopes and excerpts of a letter's content.

The newly-issued stamp will be available on the postal network from October 9, 2021 to June 30, 2023.

Universal Postal Union and UNESCO launched the UPU International Letter Writing Competition in 1971.