David Weaver
hollow grinding with CBN or even any graded wheel doesn't harm japanese chisels.

I don't do it because it's not aesthetically pleasing, but I've never noticed any issue as I may grind used chisels or plane blades initially if they show up basket cases.

Their temper isn't as fragile as people like to contend - temper at 300F is often an unusably hard japanese chisel and the effective temper for a really hard chisel made of white 1/2 or a swedish equivalent will be around 325F.

The steel on japanese chisels sparks so well that the backing metal gets hot and not the edge, and they become undesirable to handle. Not saying that someone can't stab them into a burned edge, but they grind better than their reputation would suggest.

As far as a soft ark vs. an abraded trans or black stone, it's not that easy to make a blanket statement. A dan's "soft" or a norton may be as fine as a finish stone or close once they're pretty much shut down, but they don't produce an edge finer than the one I showed as abraded.

The other softs available (smiths, natural whetstone, "case" branded, etc) will never work as finely as the abraded trans or black pictures here, and there is a range of suitability - 400 grit diamond hone on a trans or black stone is never going to create the kind of aggressiveness that much deeper scratches do.

But, trans and black stones are expensive and that's washita territory (almost all washitas).

There is a bigger difference between washitas of grade than of age. I made the comment that some of norton's later washitas are unimpressive, but I think they had given up on grade under the behr manning label and sold stones they may not have earlier (the ungraded type that just say "washita oilstone"). The behr manning graded stones (no 1, lilywhite) are still good stones, and there are very very fine older stones, but they are not as common and usually are placed in a razor box.

I get the inclination sometimes to stock washitas and grade them and sell them at cost, but the way they've caught on some, it's hard to get them in the states and I'd need to charge $80 just to break even.

The reason I'd even do that is that most people don't complete sharpening. When I put videos on youtube suggesting a grind and then a hone at a higher angle with a washita (no other steps), that suggestion was to help people understand what a completed edge is like. It's immediate confirmation that someone using finer stones isn't completing the job when they come back with "I'm getting better edges than I have before". Then, with that understanding, they can go back to their finer stones and start to make a decision about whether or not they can get enough better of an edge with finer stones than learning to use the washita well. The reality is that other than for paring chisels and carving tools, the answer is usually no. Some familiarity with any decent washita will yield edges at least as good as an 8k waterstone with a very desirable wire edge quality (fanned out, thin and not damaging when it comes off).

It usually results in some kind of shock that such a poorly regarded stone has existed among us and can do the job so easily.

Kind of like finding out that remington's new rifle model that's got tons of "improvements" isn't as good as the one dad had from 60 years ago.