The border skirmishes that make up the Kneck River Wars mean that territory is constantly lost and gained. What was a Zloblenian village finds itself in Borogravia temporarily, and vice versa. Much to the delight of flatalelists what happens on Roundworld happens on Discworld. Stamps of the occupied territory are overprinted for the use of the conquerers. These are proper overprints (unlike the Bad Blintz booklet stamps) and hand applied, going by the randomness of application, We have examples of the Borogravian 3p stamp overprinted Zlobenia 2z, with the arms of the principality. And we have the Zlobenian 2 Zloty overprinted with the Duchess’s bust in silhouette and 1p. Unfortunately they managed to mis-spell Borogravia! Luckily no sports were overprinted - it may have been hard to spot these under the overprints.

These stamps do raise a sticky (pune intended) problem. When they are mentioned, frequently they are referred to as coming from the original country. But look at any official stamp catalogue, and they will be listed under the country that applied the overprint. Thus those show above are, on the left, a Zloebian 2z overprint on a Borogravia 3p, and the other a Borogravia 1p on the Zlobenia 2z. The former should be listed under Zlobenia.