About This Item
Shobu Karasu Japanese Natural Sharpening Stone 1541.2g (3Lb. 6.4oz.)
It is a beautiful Karasu for sure especially when it wet.
202mmX74mmX37-39mm for final sharpening for razor or very fine grit sharpening for high carbon steel blade
I have got this Shobu from one of the whetstone company in Kyoto. The company used to mine Shobu (one of them, I think that Shobu had been mined by more than one company. There were more than one ore port owned by more than one company) and the other mines.
In this time, I asked to get the whetstones for razor final sharpening (hard and very fine grit) to the company.
Shoubu-dani1 is the original mine to get high quality Japanese sword sharpening in Kyoto, and the mine run out the production of the ore, and moved to the other mines, so Shobu-dani used to have really great final finish whetstones.
It is condensed hard Shobu asagi Tamamoku whetstone, and it raises good amount of slurry (it dark color stone, so it is hard to see, but it raises slurry, but it is not a lot. I mean what it should be good enough for sharpening). It might need Tomo Nagura or a device that raises the slurry by the Diamond plate, but it is smooth stone, so for me, I do not need tomo nagura.
(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 bright silver color to semi-mirror finish, and Hagane to mirror finish. Shobu is located on close by infamous mines such as Okudo, Ozuku , Nakayama, and Narutaki, where is the east side of Atago mountain. It is original mine of Awasedo in Kyoto since 800 years ago.
Natural whetstone has wider capacity wider variety 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.