Here is a link to a Czech patent from 1952.
As the story goes, Karel Drbal, the owner of the patent discovered during a trip to the Cheops pyramid a fully conserved rat in the walkways of the pyramid and started experimenting with pyramids when he returned home. He did several experiments with plants, water and also razors.
In short: if you put a razor at the height of the gravitational center of the pyramid and orient the sides of the pyramid neatly north-south, the razor will sharpen itself. Microstructures of the steel will start to re-organise themselves and make the razor sharper as a result. Happy reading.

Republic of Czechslovakia

Lol, I should try this some day. Getting 111 shaves from one Feather blade sounds interesting...
>Herman