I honestly skimmed most of this thread, but just wanted to pop in and share my love of for the Aoto Ken sold me. Solid 2-4k stone, probably one of the best meat cutting edges IMO. Particularly, I sharpened a Takeda AS 210 suji (sold as a yanagi) and it melted through these steaks I was cutting. Something about the "type" of teeth.
That's the great thing about naturals.. it's a "type" of edge, even though there's a general "grit" rating that can kind of be applied to them, there's something unique about how each stone reacts. Oh, I'm not getting started on this natural kick again, I've got too many other projects going at the moment! LOL
Later you knuts!