It is a rare whetstone. It is a whetstone that is often sold in the Kansai area and is not so famous throughout Japan.
It has hardness and is suitable for sharpening knife edges and sharpening knives.
Since the amount of mining was small, it is now a rare and valuable whetstone.
It sharpens sharply and sharply even though it is hard.
The quality is fairly hard, there is little deformation due to use, and the blade is very good.