cannabineer
Ursus marijanus
I’m a big fan of differential tempering as practiced by the blacksmiths of Japan.I'd have to do some more research on what works. But maybe electric ovens and oil baths. Or if needed fire. I do know there is clays you can use so the edge is a different hardness. I'm sure it's a art more than a process with knives.
One of two knives makes it through the “honyaki” process, which is analogous to how the swordsmiths temper a weapon.
It makes for a glass-hard cutting edge supported by a milder, less brittle temper in the blade’s back and sides.
After a lifetime of using forgiving but quickly-dulled knives, my firs J-knife was a game changer.