Abstract: A blade for cutting grass; used within a rotary mower. The swivel-mounted blade has a lower facet parallel to the plane of rotation along one edge, and a lifting surface, which meet at the cutting edge at an angle. Wear, particularly on the facet and also the lifting surface maintains the cutting edge during the life of the symmetrical self-sharpening blade. The lifting surface undergoes wear while blowing cut material upwards while suspended in air. The blade is also suited to mulching and agricultural mowers, and may be made in reversible form.