Flattening StoneIn order to maintain optimal performance, it is important to flatten your water stones. This 220 grit Naniwa Flattening Stone is specifically designed to work with Naniwa Water Stones, but it has been found to be effective on any waterstone. Before use, soak the flattening stone and the water stone, as needed. Place the water stone on a work surface or hold it in your hand, then use the Naniwa Flattening Stone to rub it until it is perfectly flat. The