With the large flattening stone from the Japanese knife manufacturer Kai, sharpening stones can be smoothed out again. This significantly extends their usability. It is almost the same size as the typical sharpening stones used for knives.

Move the flattening stone in a figure-eight motion over the stone until the desired result is achieved. The flattening stone (also known as a dressing or leveling stone) smooths out depressions or unevenness in the surface of the used sharpening stone and rounds off its rough edges.