The current Toishiyama is a mountain called Mizunashiyama.
Next to it is a mountain called Kokzo Peak.
The name of Mt. Kokzo seems to have come from the fact that Kokuzo Bosatsu was enshrined there.
Iyomeito's Kokuzo whetstone has a plain grayish-brown pattern, but it is a whetstone that seems to have been cut out from a part of the void, and to have encapsulated the eternal nature. It is very hard and often has fine grains.
By using a diamond whetstone or Nagura, it can be sharpened very smoothly.
It acts as a semi-finishing.
*The 9th image is after pouring water.
The 10th photo shows the amount of water coming out after 20 rubs.
The 11th photo was polished without removing the mud beforehand.
The 12th photo is polished after removing the mud.
