Vintage Unknown Renge Suita Fine Grit Japanese Natural Sharpening Stone 1lb. 12.4oz. (806g)
188mmX65-68mmX22-25mm
It has very nice renge dots, and 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 about 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.
Hardness-------------8.6
It raises very good amount of black slurry quickly.
It is smooth and easy to sharpen my blade.
My blade felt the surface of the stone lines very slightly, but it doesn’t leave any scratches.
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----------8.6
It makes my Swedish pure carbon steel / soft iron blade knife;
Jigane became frosted silver color finish, and Hagane became semi-mirror finish.
It is not too hard and not too soft, ideal hardness stone to me, and it makes fine finish.
Overall, it should be very nice finishing stone for single bevel edge blade with soft iron.
(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.