NARUTAKI AWASEDO Maruichi Nashiji for Razor Sharpening Japanese Natural Sharpening Stone 15oz. (420g)
107-140mmX73-75mmX18-22mm #6000 to #10000 for final sharpening razor blade or fine finish high carbon blade
Narutak-toi is the fine grit stones yields from Narutaki, Umegahata, and Takao area.
It raises very good amount of black slurry quickly. It does not need slurry stone (tomo nagura) or worn Diamond lapping stone to raise the slurry. (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)
It makes my blue II steel kasumi blade knife Hagane became mirror finish, and Jigae became bright frosted silver finish.
(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)
Narutaki whetstone is finest whetstone that is mined in Kyoto for almost 900 years. It had been very important as military affairs in Samurai era, because it is sharpener for weapons, so the mountains had been protected by the Emperor of Japan or Shoguns or Government for hundreds of years. Only Honma family had mined the mountain for a long time. Narutaki-to is used for Japanese sword sharpening and polishing, but smaller or lower quality ones had allowed to use for Kanna (Japanese plane), Chisel, Kamisor, etc.
Probably #6000 to #10000 grit with the same as artificial whetstone. When we sharpen it with usual amount of force from the top of cutlery, it might be around #6000 to #10000 grit. 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.