A couple of U.S. Western-style knife makers did blades with a combination of different grinds. For example, a convex (lenticular) grind adjacent to a concave (hollow) grind. I am not sure this sort of thing is anything but aesthetic for most knives, but I can see how a strong tip grind for thrusting penetration without breaking followed by a sharp slicing grind might be useful, ignoring the potential stress points on the blade. These sort of blades have what is known as a “Nightmare Grind” because they are a nightmare to hand grind though easier to machine on a CNC machine! I thought about what kind of Butterfly Sword might appeal to a knife collector, and was advised that unusual grinds were popular these days so I doodled out a Nightmare Grind blade that would be flippable. I sent it off to Forge Master Ali for him to do a prototype. He decided to do a concave/concave combined grind instead of the easier convex/concave I recommended and found it quite a mouthful, so much so that he said the knife had to be put in the hands of someone who could appreciate the difficulty of the work.
