[Bill Harsey]

Edge geometry, the angle at which each side on the blade comes together to meet at the final front of the working edge determines how well any given blade will cut. The strength of the steel is always the determining factor in how thin we can make the edge to cut with least possible resistance without bending or breaking. Another factor is mass because with any edged tool designed for hard strikes and maximum penetration will have to have some weight. The mass of a blade is limited by how fast or for how long the human user can make it work. Mass adds thickness and this causes changes in edge geometry. All the above has to do with sharpening a sword. It is usually a lot more work than a knife blade because to sharpen correctly, you have to remove a lot of steel, with a high degree of precision, along the entire side of a sword blade to maintain a good cutting geometry that cuts well. It is rarely a matter of just a simple sharpening bevel at the front of the edge.