The tip of the sword is cut at an angle and is hammered out using a small mallet. Any surface unevenness is then removed using a file. After that, the fully formed sword is tempered for strength and sharpness. The unique temper pattern of the Japanese Sword depends on how the soil is applied. Heating the sword with the soil applied and then suddenly cooling it in water is called tempering. The line and positioning of the main part of the sword body are decided by removing deformations from the tempered sword and aligning the shape.