Sorry for taking so long to get back to this but last week was very short for me.
Well, here we have the blade after heat treatment, and you can clearly see its temper line, wich is the result of not introducing the blade completelly into the oil, so the edge will loose heat much, much quicker than the back, leavinf the former hard and the later soft. This works with most carbon steel.
Also, notice the color and general aspect of the blade. I use to leave this finish, that is a product of the heat treatment andis known as “kuro uchi”, widely used in traditional Japanese baldes, on most of my carbon steel baldes. It not only is an excellet rust deterrent as well as it leaves a certain rustic finish that has aways pleased me. When the knife it new it may loose some small chips of the finish during use but that´s normal and expected.