Vintage Hatanaka Umegahata Awasedo Japanese Natural Sharpening Stone 1188g (2lb. 10oz.)
It is in Hatanaka paper box, and sticker, and stamps. It is very nice condition under the paper sticker (no damage or lines or unwanted objects). Hatanaka Toishi Co., used to sell lots of variety of the natural sharpening stones included in Nakayama maruka. I do not know which mine it was from. According to the sticker on the sharpening stone, it is from Umegahata, so it could be Nakayama, Okudo, Narutaki, Shobu, etc
206mmX76mmX31-35mm It should be great for high carbon cooking knife or Japanese plane or chisel or razor
It raises great amount of black color slurry quickly.
(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------ 9.0
(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 semi-mirror finish, and Hagane became mirror finish. It looks like high quality Nakayama.
Probably around from 10000 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.