Ohira Iromono Awasedo Japanese Natural Sharpening Stone 791g (1lb. 11.7oz.)
140mmX82mmX28-29mm, around #4000 grit; Middle range fine grit stone for high carbon cooking knife or Japanese plane or chisel
Hardness------- 8.3
It raises very good amount of dark slurry quickly. It is soft side hardness in the fine grit stone which is easy to raise good enough amount of 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)
Particle Size------ 8.2
(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 light color silver to semi-mirror finish. It should be great stone to finish for high carbon steel blade, but it is not finest grit stone.
It is from Ohira mine where has been mining five generations of Ohira whetstones. Ohira mine produces Awasedo (fine finishing whetstone), Suita, and Uchigumori. Ohira is very famous whetstone as Japanese sword sharpening hone as Uhigumori. 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.