The hardness is a non issue. In fact, both YXR7 and ZDP-189 are not very wear resistant steels. My YXR7 blades both sharpen up ridiculously easy, but the catch is trying to maintain a fully convex grind/edge while trying not to ruin the mirror polish.
Lately, I've been running a little trial. I have been sharpening my Higo-X (Honzukuri) with methods that keep it all convex. However, my Chi (Shinogizukuri) has been sharpened on a ceramic stone like its a V-ground edge lately. The fully-convex shape is no longer there, the mirror polish is still intact, and it also seems to cut better and take a more keen edge.