Once in a while we happen to receive an inquiry for an old Russian patent (or rather Author’s certificate as it used to be known back in USSR days) which does not come up in the list of official patents published in Russian patent office database.
As a rule, the reason is that this very document is classified: patent was granted and it even gets mentioned somewhere (once people happen to find it), but it cannot be retrieved due to being classified.
I saw quite nice example of such a classified patent today while visiting with my 7 yrs old kid Mikhail Kalashnikov’s museum in the city of Izhevsk, Russia. Kalashnikov got a classified patent for submachine gun – actually, that was just a prototype of AK-47, or even prototype of some vital parts later used in the design.
Filed under: russian patents