If you are wondering what this stone is like to use here is the tips and tricks that was sent to me
This is one of my favorite stones for kasumi work, and I'd like to help if I can. Here are some tips & tricks I've picked up...
Red Aoto
#1 - Never, EVER dry this stone out. It will crack. That's not the end of the world for reasons I'll go into later, but if you want it to stay in one piece after it is perma-soaked (Which it benefits from.), keep it soaked until you're ready to say goodbye to it.
#2 - There is definitely some sample variation from the maker that Maksim and Shigefusa are using for this one stone. I've had 3 of these stones so far, and one was very different from the other two. That oddball cracked from S&G use, and was kind of weird in general regarding feel and polish, but still was useful after. Maksim sorted it out, no problem. He's a good guy. Most are probably good, but you kind of have to look out for those oddballs. My second cracked after I started neglecting it and letting it dry out (Albeit, slowly, as Jon Broida advises, wrapped in a wet towel.), but it still happened. I think these stones are too thick to dry out evenly. I'm now on my third, and that feels like the last, 'good' one.
#3 - This is one of those stones that creates its own polish if you give it a bit of time and pressure in a small area to build some local mud, and sort of 'break in' the stone in that spot. Doesn't matter what you've done before, it'll get erased, and if you keep going (With more pressure on the cladding.), mud will form, and with short, localized strokes, you'll start building a whole new kasumi contrast... It looks like it's going wrong, but keep going. Get some mud with a bit more pressure on the cladding, then lighten up, and surf that mud for awhile to get it uniformly matte. This stone can get crazy muddy with soft metal, and high pressure in localized areas (Just like good J-Nats.). Then, move down to the core with some heavier pressure, and polish it up by the edge. You can then sort of rock between the two points with a bit of practice to even out the finish on more convexed geometry, or, do the following...
#4 - The JNS Red Aoto is one of the only synthetic stones I've tried, that makes awesome finger-stones. If I hadn't had some crack on me, I'd be tempted to buy another just to cut up, and make finger stones from. Finger stones from J-Nats are typically too fine to efficiently fill-in overgrinds on blades, but these ones from the synthetic Red Aoto can. Build some mud by rubbing the finger stone against another bit of the core stone, transfer that mud using your fingers to the blade (As much as you can.), and then get to work. Use lighter pressure with finger stones than with bench stones, and focus on evening out the cladding rather than the core. Finger stones suck at polishing the core. Can't put enough pressure on them. Even if you have streaks on the core, you can even those out using Red Aoto finger-stones, providing you get the core polish right. It's not always needed, but can help, if the blade's geometry is uneven.
#5 - Letting the stone dry out a bit, helps with the finish. Build a heavy mud (Splash as much as you need.), let it get to a medium saturation, then use light pressure on the cladding. After, don't splash, let it get a little dry as you keep working, and apply heavy pressure on the core. You'll get an awesome polish. The same happens with soft, mid-grit stones, but is a little more forgiving. You'll screw up the first couple times you do this (You'll streak the cladding.), and then you'll nail it. Keep going. Dedicate some time to learning this technique. It'll work to get a higher polish on the core, even on your lower-grit King's, without losing that strong mist on the cladding.
#6 - Save the mud. This stuff is gold. Once you're done, buff the blade with some of this stuff on a towel (Even a paper towel, though this isn't ideal. Very short-pile microfiber is best. Low-GSM. I like Microfiber Madness Slogger towels.). The contrast will drop a little, but the overall polish will increase, just like on J-Nats. There's definitely some natural stone material in this thing.
#7 - The area you concentrated on to build up mud, will get dished, but it will also get sort of 'broken in', and if you're convex sharpening, becomes a sort of sweet spot. This spot will be your best zone for polishing. Moving to new, 'virgin' zones of the stone will not polish as well, and will be more likely to create streaks than that dished area, you've build up mud in... This stone is a piece of piss to flatten, so don't worry too much about wearing it unevenly.
#8 - The JNS Red Aoto is so soft, I struggle to get a good edge on it unless zero-grinding, or on a very high-HRC carbon immediately post-flattening. I almost always micro-bevel after this stone on something else, to avoid edge-rounding.
