Allan, that hamon is a very distinct differential heat treating process.
Below is very hard, and in and above the bottom edge of the hamon will not be hard.
W2 is a VERY shallow and fast hardening steel, and just a little clay will produce some great hamons, which, by the way, was part of the thought process in making these Club Knives - they not only had to perform well, but had to be "special" as well.
The "heat treating process and the concepts" is directly proportional to the steel type and the task the knife is intended to perform.
The performance of the given steels that I intend to test is already well known, but it will be as much for a magazine article and promotion of Andersen Forge as anything else.
I will probably use my "special" 1984 5160, W2 and 1095/15N20 Damascus as my control knives for the test.
I'm going to a hog hunting camp for a week in Texas with a bunch of other Trad Gangers and want to use those three knives side by side until they give out, keeping notes and records along the way.
We'll see!