I figured for $15 I couldn't go wrong ordering a closeout Amakusa for the EdgePro. While there were no reviews for the EdgePro version, the reviews on the full size brick
But I can't for the life of me get this stone to do anything. It slides over my Tojiro Shirogami Nakiri
as if it were a slab of plate glass, not a sharpening stone. There's next to no "gritty" feel to it at all unless I really bear down on it, stressing the EdgePro arm, and even then it just barely
feels gritty. The Tojiro Shirogami line may have its faults - can we say "reactive"? - but difficulty of sharpening is not one of them. My Shapton Glass 4K feels way
grittier and when used as a follow-up to the Amakusa almost instantly started to show removed metal from the Tojiro - like within a single pass - whereas after at least five minutes of sliding it back and forth over the knife's blade the Amakusa showed not the slightest hint of either mud or any removed steel. There was just a slick wet surface jeering at my paltry efforts.
I don't have a Nagura stone but I used the 400 grit side of my combination 400/1000 diamond plate to see if I could raise a slurry, thinking that maybe the stone had been accidentally coated with lacquer or resin or something. The plate definitely sanded the stone down as evidenced by the powder left behind on the plate, but the resulting new surface behaved identically - slick as plate glass, not the faintest hint of abraded steel particles anywhere to be found after several minutes of working on the Tojiro. I decided maybe it needed to be soaked for a while, so I dunked it in water for ten minutes and went back at it. No difference.
I had hoped to use the Amakusa as my 1K, as that's the approximate range the description on the website pegs it at, but it's obvious that won't be a viable strategy. I'm now looking at either a Chosera 800
or a Shapton Glass 1K
I'm baffled and unhappy, and definitely not seeing the appeal of Japanese naturals.