Science of Tatara and Japanese Sword,
traditional Japanese methods for making steel and sword.

Tatsuo INOUE
Professor, S.A., Saitama Institute of Technology
Professor Emeritus, Kyoto University

Tatara system of preparing traditional Japanese steel, Tamagahage, from iron sand is introduced from the viewpoint of science and technology. Some artistic drawings, Emaki, painted over 100 years ago are presented to know the classical Tatara system as well as acting system in Shimane prefecture. The characteristics of the steel is excellent from the analysis of modern metallurgy. Producing cost is, however, so high, almost hundred tines expensive compared with modern steel, which is the reason why the y is propounded for sword making.

In the second part, the method of manufacturing the Japanese sword is summarized. As an example of the application of the developed theory of framework of metallo-thermo-mechanics, quenching processes, a Japanese sword is focused, and the change in temperature, metallic structure and stress/deformation are simulated. The results reveal to represent such real situations, especially modes of sori and hamon.

The discussion from the viewpoints of metallurgy and mechanics are carried out in each section of preparing traditional steel and manufacturing the sword. In conclusion, it is noted that the technology surviving for over thousand years is really consistent with the modern science and technology.