For Karitekitaneko Only: Natural Whetstone, Kyoto Origin, 1+4

This is being sold because my great-uncle, who was a carpenter for many years, has retired. According to my great-uncle, this used to cost one month's salary back in the day. He said it's a whetstone from Kyoto. It has brown markings, but it doesn't seem to cause scratches or damage when sharpening. The area around the sharpening surface has been protected.

However, I don't know much about it, so I'm listing most of them at the same price.

Please judge the size, shape, etc., from the photos.
Based on my experience sharpening with a small deba knife, it feels a bit hard.