This vibrant 1973 Polish commemorative highlights the introduction and importance of the Pocz­towy Numer Adresowy (Postal Code System). Designed with bold geometric forms and modernist colors, the stamp features an example address label representing standardized mail addressing in Poland. The miniature stamp motif in the upper right reinforces postal identity, while the clear “01–029” code symbol underscores the campaign’s educational purpose. A desirable thematic issue for collectors of postal history, typography, and modern design.