Handy tool used for flattening sharpening stones. Japanese Repair Flattening Stone/Sharpening Stone by Naniwa with gradation of #220 (this is the same product as Naniwa IO-1142)

The straightening whetstone quickly corrects trough on the whetstone You can use emery for a more beautiful and faster finish Particulate density 220.

When sharpening knives on stones, it's necessary to periodically correct the abrasive surface. The best option is to do this regularly before each sharpening to avoid the need for lengthy, one-on-one grinding.

For this purpose, grinding stones are used, characterized by a lower grit (usually 100 or 200) and deep grooves on the surface. Grind one stone against the other several times until the surface is even. To make the task easier, you can mark the grinding stone with a pencil, draw an "X" or "‡," and when the pencil is worn away, the stone can be considered even.