Vintage Renge Suita Japanese Natural Sharpening Stone 1586g (3lb. 8oz.)
It has stamps on the bottom of the box. Maru Kyo, Honsuita, and 30kiri (size)
It has a stamp on the one short side of the side face. It says Maru Kyo and 30kiri
I do not know which mine it was from. It might be Ohira suita or Okudo suita (my big guess it could be Okudo) or Okunomon suita or somewhere else mine in Kyoto.
It should be great for high carbon cooking knife or Japanese plane or chisel
It has beautiful renge pattern on the sharpening surface.
It raises good enough amount of black color slurry quickly. It is pretty smooth stone on the sharpening surface. It looks also heavy condensed stone.
All the lines and objects should be no problem for sharpening when I tried to sharpen.
(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------ 8.9
(Scale; 1 to 10, 1-3 give deep scratch marks to the steel, 3-5 is delete the 1-3 scratches, 5-8 makes the steel cloudy, 8-10 makes the steel semi-mirror finish or mirror finish)
It makes my blue II steel blade knife Jigane to frosted silver color, and Hagane became semi-mirror finish.
Probably around 6000 grit or higher. 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 (it also shows Damascus pattern vividly), and Hagane as suitable Hagane color. It is natural mystics.