Stones are the best way to grind, sharpen and polish a cutting edge. This method is also used by Japanese knife factories.The Masahiro L-3000 Super Fine sharpening stone is a flat, rectangular stone with dimensions 210x72x27mm and a gradation (number of grains, abrasive particles per cm 2) used for final smoothing and polishing of the blade. The thin edge becomes even sharper and stays sharp longer. The stone was placed on a plastic base equipped with rubber, non-slip feet. Before use, the stone should be placed in water for a few minutes and should not remain dry during sharpening.For knives, Masahiro recommends the following gradation selection: 100 - 600 for very blunt knives and with a damaged cutting edge 800 - 1000 for regularly sharpened, slightly dull knives 1500 - 3000 for final smoothing and polishing