Obrigado, Marcelo - Very interesting thread. I was thinking of starting something like this.
In the past year I've got 2 grits of Atoma diamond 'nagura' (I think they were labelled) off the infamous CooksBladesTwoGo. They seem to be a third or a quarter of a normal Atoma plate, cut and glued onto a bit of wood. I got them, good idea I thought, and then smoothed out the (too many) rough edges and lacquered them for looks and feel, and then used them. They seem not to have been mounted uniformly and wore quickly in a non-consistent way. Was the mounting wood not flat enough? At any rate, duh!
Recently I got a made-by-Atoma 400 grit diamond slurry stone (blue plastic handle thing; had searched for these by never seen them before) from Aframes which has worked better. It was still rough-ish around the edges, and I think released diamonds 2 or 3 times, before calming down. The others above were more square-shaped which I liked, and the authentic Atoma is more rectangular, but it's performed better. Takeshi of AF says this is what he uses too.
I'd say if you're sharpening razors (I don't) you'd want to follow the gentler traditional techniques and flatten/maintain stones by rubbing with other stones, not diamonds. Rushing isn't the point, anyway. I also got a kick out of this comment, which probably has some truth!
I disagree. An extra fine diamond hone will make slurry quickly and reliably, and will not wear out a natural stone in my lifetime. People who push naguras are, in my opinion, people who are trying to sell naguras.
Poor Maxim, but thanks, Rick.
However, with knives and layered gotogi finishing stones I don't think it's a problem using diamond nagura to work up your slurry. If you want to only experience slurry from that single stone, this is surely a good and fast way, provided you don't wear out your stone prematurely - because your nats should last your life.
When it comes to non-layered naturals (like the Tajima and Aizu you have, Marcelo) they're so strong and dense that I think you could diamond-away at them for years and years. Natsuya too, because while it's softer it's still so big. If with experience with razors you find the slurry's too aggressive or rough on razors this way, I don't know. But for me and knives, I wouldn't think twice.
Marcelo - I've had a few good discussions with Tomo Keith, and you might try asking him too, then posting here. In my experience he doesn't mind at all if you use his words, though you could ask first. Real razor stone nut.