In philately a perfin is a stamp that has a certain type of perforations. The word is a contraction of perforated initials or perforated insignia. (These stamps also go by the acronym SPIFS — Stamps Perforated with Initials of Firms and Societies.) But what are these things? Why are they perforated?
There was a time when post offices would buy back unused stamps if customers took them to the post office. Large businesses and organizations who used a lot of stamps worried that employees (or perhaps somebody else) would steal their stash of stamps in order to sell them back to the post office. So they perforated the stamps. The post office would not buy perforated stamps back, but the stamps would still be valid for postage. Different businesses would perforate their stamps in different ways, usually using some combination of letters that would reference the corporation’s or organization’s name. And they would end up looking, for instance, like this stamp here above.
This particular one, a stamp from Bosnia and Herzegovina, has a perforation of Cyrillic letters that says С.Б.М. This is the initials of Serbische Bank in Mostar (in Serbian I think Serbische Bank Mostar would be written something like this: Србска Банка Мостар).
We can also read from this stamp that it is created during the time when Bosnia and Herzegovina was occupied and administered by Austria-Hungary: K.U.K. (printed in the upper left corner) stands for kaiserlich und königlich — that is, imperial and royal — which refers to Austria and Hungary, respectively.
On the stamp is the portrait of emperor Franz Joseph I of Austria (1830-1916). Franz Joseph I had an eventful life, with a good amount of personal tragedy. His brother Emperor Maximilian I of Mexico was executed in 1867, his son Crown Prince Rudolf committed suicide in 1889, his wife Empress Elisabeth was assassinated in 1898. And then, in 1914 in Sarajevo, Gavrilo Princip, a Bosnian Serb, assassinated the heir to the Austro-Hungarian throne, Archduke Franz Ferdinand, who was Franz Joseph I’s nephew. This is widely considered to be the event that sparked World War I (1914-1918).
The stamp in the picture, the Bosnien Hercegovina K.U.K Militär Post stamp with Franz Joseph I, was published from 1912 to 1917. As far as I can make out from the postmark on this particular specimen, it looks like it says “MILIT.POST,” the location is Mostar, and the date is 3rd of … September, maybe … 1914, and this means it was attached to an envelope which was mailed a couple of months after Franz Joseph I’s nephew was assassinated in Bosnia.
The stamp was designed by Koloman Moser, who was part of the Vienna Secession.