I discovered this while figuring out how to do a modern Japanese temper line: 1 remove the handle from the knife or you'll ruin it completely! 2 Clamp two pieces of heavy angle iron over the blade,leaving only the edge exposed.the idea is to have a soft spine and a hard edge so it won't break the knife! 3 using a propane torch,heat it dull red and quench in oil,for stainless steel,use ammonia. 4 Buff the blade,if you did it right,the steel will have a discolored/dull edge that never will match the spine,but now will hold an edge like crazy! Now for the slick part.if you make knives,you can grind waves into your chill blocks[the angle iron]and get an authentic Japanese temper line!