I was referring to the very first Pokémon series I played on my GameBoy as a kid. You could give the Pokémon different kind of stones to evolve. The thunder stone let them become electric. Long time ago.
This type of grind is pretty self explanatory and shown in the diagram. The main grind is flat, and ends closer to the spine are of the knife. Where things can get confusing with this type of grind (and a full flat grind) is the secondary bevel. It can be a v-grind, a convex grind, or a compound grind (which is multiple angles of a v-grind closely simulating a convex grind).
People tend to get confused because someone will say that they put a “convex edge” on their knife. It often gets interpreted as a full convex (referenced earlier). Obviously, putting a full convex edge on a high flat ground knife would be very difficult. What they are usually talking about is the secondary bevel has been put on with a convex profile. To see more about doing this, and how to do it, please visit the sharpening area of this website.