I haven't read Mr. Johnson book but from the excerpt, he would seem to have a basic knowledge of japanese forging techniques, or at least what they are today, and doesn't go into much detail. I would not boast to know more than him on the subject of metallurgy and forging. As for saying which technique was used the most in the Sengoku period, I have no idea, different regions had different techniques and I'm not aware of any document that examines the numbers.
At any rate, I would ask again for references on the Rockwell statement that you made, Mr. Chouinard. And I would also ask that you reference a bit more so that the debate may continue in a scholarly manner.
Actually the article I linked did mentionned that the edge was of a higher RC in general. Everything else if from personnal experience and those of other people. If you need a source, I might not be able to give you what you need, but I do remember a mention of a study of historical european swords based on their hardness, it was mentionned a couple of times on myarmoury. I'll try to find it but I'm in a bit of a hurry right now.
And to this you have said that the Edo period brought advancements in metallurgy. I would like to see some citations, please. I do not know when the Edo period was, so that does not help to prove anything.
Actually it was not really an advancement, practically speaking. Here's an article about it (badly translated though): http://www.k3.dion.ne.jp/~j-gunto/gunto_145.htm
As for the Edo period, it is a period between 1603 and 1868, of relative overall peace (some invasions, rebellions etc, but sporadically). The shogunate authority assumed near complete authority and Japan was for the most part closed to the outside. Most common myths and beliefs about the samurai come from this period. http://en.wikipedia.org/wiki/Edo_period
The period before is sometimes referred as sengoku era . It is the warring states period during which the various feudal lords battled with no interruption for control of the archipel, and later for Korea-China. It started around 1467 and lasted roughly 200 years.
http://en.wikipedia.org/wiki/Sengoku
And let us not move into the fine artistic examples that are possible, let us stick to the grade of weaponry that could be found on the battlefield, that was made for it. Pieces in peacetime, from both countries will have beautiful pieces that will only serve to drag this discussion away from a possible outcome.
Not sure what you are referring to, where was I discussing the merits of aesthetics? I have no interest either into discussing it here.
Final question: At which part of the blade are you saying the Rockwell is higher? Overall, Spine, edge, middle? That might help here.
Again depending on the method of construction, but most of the time the edge and the point area would be.

