Vintage Aoto Fine Grit Japanese Natural Sharpening Stone 4lb. 8.3oz. (2048g)
230mmX55-57mmX55-60mm
***It has lower spot on the middle of sharpening surface on both sides.
I tried to make them flat with belt sander, and it is hard stone, so one side became flatten all the way, but it has to work on much more to completely flatten the stone. The other side of the sharpening surface has to flat as well. If you want me to do it, I can help one side of sharpening surface flatten, if you ask me after purchase it***
It is very heavy stone for the size, so it should be very condensed stone.
I found it here is Hawaii.
Hawaii has a long immigration history from Japan (I guess it has been over 160 years), so Carpenter, barber, cook, fish cutter, butcher, etc. needed good sharpening stones, especially carpenter and barber needed high-quality fine grit stones in old days (until King synthetic red color sharpening stone came up on the market in 1960s, Aoto is the main medium to medium high grit sharpening stone).
Hardness-------------8.9
It raises very little amount of slurry, and it has smooth sharpening surface, but it is very hard stone. It looks like a hard fine grit stone.
It looks it does not need tomo nagura or the device to raise the slurry (worn Diamond lapping stone).
(Scale; 1 to 10, 1-3 is very soft, muddy, rough grit whetstone 3-6 is soft medium grit whetstone, 6-8 is hard medium grit whetstone; 8-10 is fine grit whetstone)
Particle Size----------8.3
It makes my Swedish pure carbon steel / soft iron blade knife;
Jigane became frosted silver color finish, and Hagane became bright silver color.
(Scale; 1 to 10, 1-3 give deep scratch marks to the steel, 3-5 is delete the 1-3 scratches, 5-8 makes 3the steel cloudy, 8-10 makes the steel semi-mirror finish or mirror finish)
Natural whetstone has wider capacity than artificial whetstone, and actually, we do not know until sharpen blade on the hone for a while. Because artificial whetstone molecules do not break down to smaller sizes, but Natural whetstone molecules are possible to break down to smaller sizes, and those molecules are mixed with sharpened steel molecules, and make Jigane as suitable Jigane color, and Hagane as suitable Hagane color. It is natural mystics.