First is d, the thickness behind the edge; the thinner the material is behind the edge the smaller the “wedge” is. Next is ß, indicating the angle of the edge. The sharpness, or edge width, is marked with b. Then b’ is the theoretical sharpness limit if the edge reached an infinitely small edge width. These are the three primary parameters that control cutting ability (see this article for more information on sharpness and cutting ability). Smaller d, ß, and b all mean better cutting ability.