I have one of those Shobu stones. I have produced some pretty sharp edges with it. It is obvious that it cuts metal. It's the only one that I have had to split on me. *shrug. Being softish it drinks deep (lotta water).

It is fine grit, makes a pretty knife bevel, to me it is a "polisher"; (easily shaped for grooves or gouges if need be. see above as it wants to do it on its own) Like if you get too much patina this kinda stone will clean it up quicly and look nice, Then I sneak an easy micro-bevel on with a hard stone.

Dudley Togi has shown some of his "mame-awaseto". This type would make a good candidate for high grit sandpaper replacement doing restoration