On October 26, 1976 Transkei, a state created by the Republic of South Africa's apartheid government, issued its first definitive series. The 50c value (Sc #19) from this set of 21, shows a map of Transkei and its coat of arms.
From Wikipedia, "Transkei represented a significant precedent and historic turning point in South Africa's policy of apartheid and "separate development"; it was the first of four territories to be declared independent of South Africa. Throughout its existence, it remained an internationally unrecognized, diplomatically isolated, politically unstable de facto one-party state, which at one point broke relations with South Africa, the only country that recognized it as a legal entity. In 1994, it was reintegrated into its larger neighbor and became a part of Eastern Cape province."