Sakai Forged Blades Stage One Blade Forging: A powder containing boric acid is sprinkled onto the heated metal stock and the blade of high carbon steel is laid on it and forged at approximately 900°C. Stage Two Shaping: The blade is laminated and beaten out at between 600°-700°C and gradually formed into a knife blade. Stage Three Annealing: Having raised the temperature to between 700°-800°C to soften and reduce an internal stresses, the blade is allowed to cool naturally. Stage Four Beating: The blade is now beaten at room temperature in order to flatten it, to fill any pits or blemmishes in the surface, and to remove any hammer marks which were produced when it was being forged. Stage Five Tailoring: Working to a standard shape, the blade is tailored and any excess is trimmed off. Stage Six Grinding: Any rough edges after tailoring are ground off and then the shape is tidied up with a file. Stage Seven Mud Coating: So that the blade can cool quickly and evenly when it is tempered, it is painted with a mud slurry, which is dried in a warm place behind the furnace. Stage Eight Tempering, Annealing: In order to harden the blade, it is heated to between 700°-800°C and quenched in water. Then in order to give the blade strength and resilience it is heated again to between 180°-200°C and allowed to cool slowly. Stage Nine Grinding, Finishing: Now begins a process of grinding and honing. First the blade is ground flat and finely honed with a stone. Then the edge is produced and the back of the blade is ground. A slight depression is produced, followed by buffing. Using a wooden staff, the ground lines and color of the blade are brought up. While care is always taken to keep the blade true, it is finally wiped over with a little oil to prevent rusting. In all, there are 27 individual steps involved in grinding and honing one of these sharp and finely crafted blades.