Not I'm afraid Japanese natural stones!
I've been experimenting with various pieces of Willunga slate, which I have access to quite a lot of. It seems to me to be quite promising for sharpening. The piece below for instance I've used a fair bit, and can sharpen my knives to as sharp as I can get them going up to my 3k synthetics. It does require lapping / generating slurry on sandpaper beforehand, takes fair bit longer than using my other stones, and gives a edge finish that seems much finer / less toothy. And interestingly I don't seem to have to do much in terms of stone progression - I just alter the surface water and pressure used. I do not seem to be able to get them to work as polishing stones, unless you want a very weird wavy not-very-good Kasumi, tho that may just be my lack of technique.
And here's another thread with some thoughts / pictures: Some questions about slate...
If anyone would like to try one I'll happily go out and find some more promising-looking examples (not all the ones I've found seem suitable), and send out for the cost of shipping. I'll flatten to an acceptable level for you, but they won't be cut into nice neat rectangles or anything fancy I'd like to hear other people's opinions on them; particularly how they compare to other natural stones, and any expert tips on the best ways of using them. Though more than happy to send to anyone, no need to be a j-nat expert!
Give me a shout if anyone wants to try. NB - I am in Australia, I'm happy to ship elsewhere, but will obviously be more $.
I've been experimenting with various pieces of Willunga slate, which I have access to quite a lot of. It seems to me to be quite promising for sharpening. The piece below for instance I've used a fair bit, and can sharpen my knives to as sharp as I can get them going up to my 3k synthetics. It does require lapping / generating slurry on sandpaper beforehand, takes fair bit longer than using my other stones, and gives a edge finish that seems much finer / less toothy. And interestingly I don't seem to have to do much in terms of stone progression - I just alter the surface water and pressure used. I do not seem to be able to get them to work as polishing stones, unless you want a very weird wavy not-very-good Kasumi, tho that may just be my lack of technique.
And here's another thread with some thoughts / pictures: Some questions about slate...
If anyone would like to try one I'll happily go out and find some more promising-looking examples (not all the ones I've found seem suitable), and send out for the cost of shipping. I'll flatten to an acceptable level for you, but they won't be cut into nice neat rectangles or anything fancy I'd like to hear other people's opinions on them; particularly how they compare to other natural stones, and any expert tips on the best ways of using them. Though more than happy to send to anyone, no need to be a j-nat expert!
Give me a shout if anyone wants to try. NB - I am in Australia, I'm happy to ship elsewhere, but will obviously be more $.