I heard edge retention on HD is better (markedly) than HD2 if you go the kono route.
Having used both, I found that the HD2 was easier to sharpen and held that edge longer than the HD. I have since sold off both of those knives however. The original HD steel is by no means difficult to sharpen, I just found the HD2 something closer to White#2 in the time and effort it took to sharpen and closer to Super Blue in the retention catagory. YMMV.
"Meat, vegetables, a fish, an all-around kitchen knife including the bread. It is unsuitable for the thing which is too hard because a blade is thin." -Engrish
Weird, I heard the opposite. Doesn't the HD2 have better edge retention and stain resistance?
Jon at JKI gets alot of Luv here & for good reason.He has some Gesshin stainless thin blades that would make great work knives.The Kono HD is a good blade,it is just that they have gone way up in price.The Sakai Yusuke stainless lazors are good blades too.
The Richmond blade seems thin & good shape,however they need major thinning to cut well.The factory just grinds a 50/50 wedge on the edge.