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Yasugi Specialty Steel and Tatara

Passing Down Technology

The special steels industry found itself following a difficult path following World War II, but research into iron sand reduction continued. In 1952, a method for pelletizing iron sand was developed, contributing to a reduction in the number of basic units of charcoal pig iron required. Hitachi Metals also commenced basic research on the manufacture of kaimen iron (sponge iron) based on the low-temperature direct reduction of iron sand, and in 1964 it built a factory for manufacturing kaimen iron using technology imported from the Swedish company SKB. Japanese iron-making traditions based on the use of the superior iron sands of the Unpaku district, passed down from the tatara of ancient times to the square furnaces of today, have been kept alive by the latest technologies.

In 1977, The Society for Preservation of Japanese Art Swords with the support of the Agency for Cultural Affairs built the Nittoho tatara on the grounds of the old Yasukuni tatara adjacent to the Torigami charcoal pig iron squared furnace in Okuizumo. The tatara was built because the Japanese steel and iron needed to make Nihonto had become increasingly scarce in the 40 years since the end of the war. Workers connected with the manufacture of charcoal pig iron have been working to master tatara operations, and at present the tatara supplies tama-hagane to swordsmiths throughout the country. They are truly passing down this traditional Japanese technology to future generations.

Tatara iron making


We hope this overview has given you an understanding of the connections Hitachi Metals has with wako and tatara. We feel confident in stating that our efforts at Hitachi Metals to use modern technologies to bring out the unique characteristics (i.e., the purity) of Japanese steel are built on a foundation of Yasugi Specialty steel.



Yasugi Works (coastal factory site)

Yasugi Works (mountain factory site)

This concludes our “Tale of the Tatara.” Thanks for reading!

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