A whetstone is a tool for sharpening a blade in order to make adjustments in micro units. It is said that sharpening is the key to cutting a blade, and it takes longer to sharpen than to use the blade. It is not permissible to neglect preparations. It takes years to learn how to use a whetstone. This is because it is not just a matter of sharpening, but the method of sharpening differs depending on the tool.
For example, Kanna inflates and sharpens the central part, and fleas conversely dents and sharpens the center. While using the whetstone, the part where the blade hits becomes dented and the shape changes, so it is necessary to think about where to apply the blade and how to apply force so as not to dent.
Sharpening a knife has some subtleties that cannot be explained by mouth. The truth is that you have to remember it with your own body, and it is understandable that inheritance is difficult.