In April 1944, the academic prof. Đorđe Andrejević - Kun prepared a conceptual sketch for the first Yugoslavian stamp. Only 20 hand-made copies were made from the pear wood cliché with burgundy color on darkly yellow paper. Due to the heavy battles in Drvar and war situation in general this stamp was never issued.
Fakes exists, even with certificates!
Essay for the first Yugoslavian stamp on the left. Picture taken from the "Catalogue of postage stamps of Yugoslav areas, 1980" on the right.
