Nagasone Kotetsu’s birth name was Okisato, and Kotetsu his Buddhist priest’s name. In his home village of Nagasome in Omi Province, he was an armorer, and later moved to Fukui in Echizen Province and spent half his life there. Around the Meireki period, when he was around 50 years old, he turned to sword making, and moved to Edo, later settling in Shitaya. His teacher is said to have been Kazusanosuke Kaneshige, and his novel style and skillful engraving, as well as the sharpness of his blades, quickly took the world by storm. His style involved slightly curved or straight blades, with very fine and beautiful textures, and he was especially skilled at creating hamon in vigorous waves or round semicircles that evoke a Buddhist rosary (juzu). The bright, vivid particles forged into the side of the blade are distinctive of this swordsmith.