To sharpen a knife you will need to get a set of stones. A "set" is usually composed of 3 steps. First step is a coarse stone, which shed more material from the knife. Second step is a sharpening stone "perse", which fine tunes the edge. Third step uses a finishing stone, which refines and polishes the edge of a knife. In addition to this 3 basic steps, there are 2 other steps that are very important. One of this steps is the flattening & thinning stone. Which are super c