So, the 1961 definitive series with the portrait of Walter Ulbricht, the Chairman of the State Council, is one that the collectors of the GDR have studied to some extent and most of it has been published in the Specialized catalogues of Germany to name the Michel Spezial Katalog as the most influential one!
Nevertheless, as we have experienced with Argentina definitives, some things have been overlooked for years!

to be continued ....