I don't really see a huge difference in most of these carbon steels in terms of sharpness. They all seem to get super sharp with minimal difficulty. It's when you get to stainless that it's tricky. It think it's funny that people talk about HT all the time. While the statement is absolutely true, there are few on this board outside of knifemakers that really know. In order to know, you have to try a lot of knives made of the same material. There is variation even between batches of the same steel. For example, carbon content for a steel can have a range of 0.90 to 1.1 % C. That is a HUGE difference, if you ask me. Even if you can feel a difference, what is it due to? What trade-offs were made? There are only a few things I think we can honestly evaluate with any sort of certainty: cutting resistance, sharpenability, toughness, grind consistency, reactivity. Even wear-resistance can be a little iffy since I really doubt most of the damage an edge takes is actually from wear. Why do you think relatively low carbon steels are so awesome? Anyway, I might have missed something but just my two cents. Get some good steel from a well-regarded knifemaker using what he likes to use and you'll be fine and the fact of the matter is that 90% of the Japanese knives I've tried have been at least very good, if not excellent or even outstanding, regardless of steel or maker.