Abstract: A nine-cornered reversible cutting plate having a plurality of primary cutting edges and secondary cutting edges on each of its upper and lower sides, the primary and secondary cutting edges being of unequal length. The cutting plate is generally shaped as a nine-sided polygon formed by an equilateral triangle whose vertex regions have been replaced by small isosceles triangles, with the primary cutting edges being disposed in the regions of the isosceles triangles and with the ratio of the length of the primary cutting edges to the length of the secondary cutting edges ranging from 1:1.5 to 1:3. The corners between the primary cutting edges and secondary cutting edges are rounded.