Research of blacksmithing technique based on experience and its ergonomic studies on the Tomari Hatchet

The blacksmithing techniques of general blacksmiths have been said to be the result of "art of intuition." The blacksmiths learned the technique by repetition of the act of blacksmithing and the accumulation of its results, comparatively acquiring the relationship between the act and the results, and the rules between them. Through these experiences they mastered the guidelines needed for the their blacksmithing. Furthermore, a high-speed-camera-filming of a user working the Tomari Hatchet revealed that the user is expressing the movement of his body, i.e., the image of the body technique, that is sliding the Tomari Hatchet by taking the advantage of its curved, long blade to cut an object.