Jigane refers to the body of the blade, and katana-kaji begin the process of making the katana by first creating the metal for the blade. Steel pieces called tama-hagane (meaning precious “jewel steel”) are made from iron sand. These are crushed into smaller pieces and heated to form one large piece. Heated further and repeatedly hammered, stretched, and folded, the steel takes shape as a Japanese sword. This 900-year-old forging process (tanren) continues virtually unchanged, creating jiigane of supple strength and superb texture.
“Normally, steel is made of iron ores liquefied by heat, but nihon-toh is formed differently. Tama-hagane pieces are never melted at high heat but only forged. This creates a quality feeling like no other metal,” Mr. Yoshihara explains.
Nihon-toh takes its distinctive appearance from hamon blade patterns shaped like waves. In the hardening process (yaki-ire), the heated body of the sword is quenched in cold water, causing quick cooling that alters the steel composition and creates striking patterns, which the swordsmith controls by coating parts of the blade with clay. Ornamental motifs depict nature scenes and town landscapes, revealing the artistry of the katana-kaji. It’s a marvel how ancient swordsmiths unfamiliar with modern steel and chemistry devised this enduring process nine centuries ago — and transformed technique into art.
Mr. Yoshihara has made more than 500 katana since becoming a katana-kaji 53 years ago. Yet he says, “I still feel excited when I can harden a sword and capture the beautiful hamon I want. Because, even after all these years, these two processes cannot be seen through to the end — there is no end. Even if I continue this craft until I pass away, I may never truly master it. All I can do is continue to strive as hard as I can.”