So recently Mike has been sharing a lot of contemporary counterfeit Ukrainian notes and so I figured that I would share kind of along the same lines.
The Czechoslovakia P#5 1000 korun which is an Austrian 1000 korun with a red stamp printed onto the Hungarian side of the note. This stamp turned the old currency of the Austro Hungarian Empire into "new" Czechoslovakian currency. These were issued in the newly founded nation for a short time period in 1919 and 1920 before new banknotes were printed and issued.
Counterfeit bills were handstamped with an additional stamp over the red stamp that read "BANK UR MIN FIN PRAHA", (Banking Office of the Ministry of Finance Prague. This was to indicate that these bills were not legitimately stamped. I'm unsure if they were stamped with the extra stamp to make them legal currency or help identify them later when the new banknotes were swapped out . But it makes me wonder why they were stamped as opposed to being pulled from circulation.
My example of this note is heavily circulated and damaged but the ink of the handstamp is still mostly visible. I don't know if this damage was from circulation under Czechoslovakia or Austria. Or just improper storage later.
I am unsure what the total population of these notes is and how many survive to today. They were issued for a very short time period in the new nation of Czechoslovakia and they were a high denomination that was not used as much as smaller currency. Currently only 1 has been graded by PMG and no counterfeit notes have been graded, and these do not come up for sale very often.