prepared stock that is larger in all dimensions than the finished sword by filing, grinding and cutting. While the technique has been available for centuries it was not widely used for making swords until the 19th or 20th century as it is wasteful of the raw material. Where iron and steel are plentiful this method is frequently used as it requires less time. In places and times where iron and steel have been more rare and valuable stock removal has not been used except as part of the finishing process. In most techniques, the basic materials, generally iron and/or steel, are shaped into a bar or billet first. At this stage, if several metals are to be used they will be combined by welding to form the billet. In some techniques, notably the traditional folded steel blades of China, Korea, and Japan, the billet might be drawn, folded and welded back on itself creating layers of steel of different types. In others longer bars or rods of steel and iron might be welded together, edge to edge, to create the basic billet placing the softer iron inside with the steel at the core and edges. Once the billet is created it is drawn out farther, generally tapering to the edge(s) and point. The technique of fullering might be used to create a ridge or ridges down the length of the blade. Whether single or multiple, the ridge's primary purpose to give the blade greater structural strength relative to its mass. During fabrication, the metal might be annealed to relieve stresses built up from forging and differential heating, and to make the metal easier to file, engrave or polish. Heat treating After the workpiece is done being formed, it is normalized. The blade is then carefully and evenly heated and afterwards cooled slowly. The point of normalizing is to remove the stresses which may have built up within the body of the blade while it was being forged. During the forging process, the blade might be heated and cooled differentially creating stress, some parts might be hammered more than others, some areas hammered enough to harden them. If these stresses are left in the blade they could affect the finishing and when it came time to heat treat the blade, the hardening and tempering might not be as even. Potentially enough stress could be added that the blade would be weak