As the Sengoku period came to an end and the world became more peaceful, there was an increasing demand for agricultural implements, necessary for the development of new fields, and various tools for city dwellers, replacing weapons. Meanwhile, in Sanjo, Japanese nail craftsmen were invited from Edo (present-day Tokyo) to save farmers from the yearly floods, and they encouraged them to make Japanese nails as a side job. This was in the early Edo period (1625). After this, the Meireki Fire of 1657 in Edo triggered a huge demand for Japanese nails, and professional blacksmiths emerged, forming settlements rather than just as a side job. Later, techniques for making machetes and other tools were introduced from the Aizu region, and various bladed tools were manufactured. These products were sold through Sanjo merchants with nationwide sales channels. Furthermore, new needs were absorbed and used in product development, creating a virtuous cycle. 

In modern times, as attempts were made to scientifically study blades, Kosuke Iwasaki, a leading researcher in blade making, generously shared his groundbreaking blade-making techniques, which involved scientific analysis using a metallurgical microscope, with Sanjo blacksmiths. This event meant that Sanjo blacksmiths came to incorporate both "tradition" and "cutting-edge science" into their techniques.

▶The path of Mr.Kosuke Iwasaki, a great man from Sanjo City who dedicated his life to creating the world's best blades