Echizen forged knives

Echizen forged knives are traditional knives made in Echizen City, Fukui prefecture, Japan. These knives are notable for the use of two techniques in its creation. "Nimai hiroge" (double layering), and "Mawashi hagane tsuke" (shaping the knife). Because of these characteristic techniques, they were chosen as the earliest traditional craft for forged knives in 1979.
History.
The origin of Echizen forged knives was in the early Nanboku-cho period. In 1337, Kuniyasu Chiyotsuru, a sword maker from Kyoto Prefecture moved to "Echizen no kuni" (present Echizen city) and made sickles for the citizens. During his stay, many citizens began to make products using his techniques. Because of this, Echizen city became an area famous for their production of farming tools. During the Edo period, these tools spread in Japan through trading. They were noted for their lightness and sharpness, and because of this, knives made in Echizen city became popular in Japan. Now, Echizen produces many products other than knives, such as hatchets.
Two main processes.
The two main important processes: "nimai hiroge" and "mawashi hagane tsuke".
...The blade is evenly thinned by stretching the two layered plates. This is done by beating both sides at high speeds with a machine hammer. 
...The tip of the blade is sharpened carefully to be close to the sharpness of a diamond.
References.
KOGEI JAPAN https://kogeijapan.com/locale/ja_JP/echizenuchihamono/
Echizen Forged Knives Cooperative Association HP https://www.echizenuchihamono.com/shop.php 
Takefu Knife village Cooperative Association HP https://tkvstore.net/