What is a "Tatara" ironmaking?

Tatara ironmaking is Japanese ancient and traditional ironmaking method. In the modern steelmaking process, a pig iron is first smelted from iron ore and coke using a blast furnace, followed by the production of steel by decarburizing the pig iron using a converter. On the other hand, in Tatara ironmaking, iron sand and charcoal were used instead of iron ore and coke, respectively, and steel was directly produced. Compared to the modern process, it seems that the Tatara ironmaking method was operated under lower temperature and higher oxygen potential.

It is said that the quality of steel made by Tatara ironmaking method is relatively high, and Japanese sword can be made only using Tatara steel. On the other hand, the productivity was lower and therefore it was replaced by a modern method at an early stage of Showa Era. However, used technology in this method is of great interest. Namely, it used powdery iron ore (iron sand) and the operation was done under lower temperatures and higher oxygen potential, which is believed to be applied to modern steelmaking. Further we believe that it is very effective for the education for ironmaking by our experiences through dozens of operations.