Used natural whetstone, likely Ozaki Aisa, large size

As shown in the photo, there is a mark of a reliable seller.
Low grit, with a cloudy finish. Moderate polishing power, good hardness, and no tendency to scratch the base.
The results were not ideal with my skill and kitchen knife, but according to the previous owner, the grit is fine and it achieves a near mirror finish, so it might be amazing with woodworking tools.
According to the previous owner, it is an Ozaki whetstone, but I cannot guarantee the origin. It feels like the moderate hardness typical of Ozaki.