Modern Swordsmith Material Selection: Tamahagane, Japanese Iron, and Western Steel in Contemporary Sword Forging

The Material Problem of Japanese Swords: Questioning "Tamahagane Absolutism"

When it comes to Japanese swords, tamahagane—this equation has become an unshakeable common understanding among Japanese sword enthusiasts. Tamahagane produced by tatara iron-smelting in Okiuzu, Shimane Prefecture is the material for "authentic Japanese swords," and swords made from other iron materials are not recognized as Japanese swords—such understanding is widely shared.

However, the reality of contemporary smiths' material selection is far more complex than what this "tamahagane absolutism" assumes. In the certification standards for Japanese sword production established by the Agency for Cultural Affairs, there is indeed a regulation stipulating "use of tamahagane or other wa-tetsu," and the use of yō-tetsu (industrial steel materials) produced by steel manufacturers is not permitted for registered blades made by officially certified smiths. But behind the absolute theory that "only tamahagane is correct," the problem of cultural identity is more deeply intertwined than technical facts. This article will specifically examine the reality of contemporary smiths' material selection and the impact each material has on sword-forging techniques.

Characteristics of Tamahagane and Their Impact on Sword Forging

Tamahagane is a product of tatara iron-smelting, an inhomogeneous steel ingot obtained by refining sand iron and charcoal over three days and three nights. This inhomogeneity is both the greatest characteristic of tamahagane and simultaneously its greatest "difficulty to handle" for swordsmiths.

The carbon content of tamahagane is distributed within a range of approximately 0.3% to 1.5%, and smiths must select the high-carbon portions (kawagane/kawachigai-muki) and low-carbon portions (shingane-muki) through visual inspection and strike-sense discrimination. Through this selection process and subsequent fold-forging, tamahagane's inhomogeneity is conversely transformed into a unique visual texture called jihada. The skin patterns of the jigane such as itame-hada, masame-hada, and mokume-hada appear as "traces" of tamahagane's impurity treatment and carbon distribution homogenization process.

The advantage of tamahagane in sword forging is that its "indeterminacy"—that chemical composition differs each time—conversely draws out the craftsman's judgment and skills. In the forge, the sense of feeling "how this iron will behave"—unnecessary with homogeneous and predictable industrial steel materials—is refined.

On the other hand, the disadvantages of tamahagane are limited production and price. Tatara operations are limited to a few times per year, and the Japanese Art Sword Preservation Society (NBTHK) manages the centralized supply of tamahagane. Production volume is unstable in meeting the demands of active smiths, and the quantity available to new smiths is often restricted.

Types of Wa-tetsu and Contemporary Usage

"Wa-tetsu" is a general term for iron materials obtained from traditional Japanese iron-making methods, and there are multiple types besides tamahagane.

Oroshi-gane is iron made by melting and refining tamahagane once at high temperature, with higher homogeneity than tamahagane. Since carbon content is relatively easy to control, it is often used as material for shingane.

Hōchō-tetsu or forge-iron is low-carbon soft iron obtained as a byproduct of tatara iron-smelting and has been used as the low-carbon portions of shingane and kawagane.

Furu-kane is iron recovered from old farm tools, old nails, and iron nails from dismantled old buildings, and there are records of past smiths using it as substitute material during periods when tatara steel was difficult to obtain. While rarely used in modern times, it is important as evidence of the "material diversity" of that era in analyzing old swords.

The Problem of Yō-tetsu (Industrial Steel Materials) and Informal Use

The use of yō-tetsu is not permitted for "Japanese swords" made by officially certified smiths authorized by the Agency for Cultural Affairs and issued registration certificates. However, there are smiths who use industrial high-carbon steel (high-speed steel, bearing steel, carbon tool steel, etc.) in the production of non-certified "decorative swords" and "iaido practice blades."

The advantages of industrial steel materials in sword making are clear. Since composition is homogeneous and quenching characteristics are predictable, heat treatment stability is high and quality control for breakage and bending is easier. In Western sword-making (blade smithing), the use of industrial steel materials is standard, and there is also a culture in the international sword market where finishing, sharpness, and balance are valued more than materials.

However, swords made from industrial steel materials do not produce jihada. Even when subjected to fold-forging, industrial steel materials remain homogeneous, so the unique skin patterns produced by tamahagane do not appear. This means lacking one of the greatest aesthetic elements in Japanese sword appreciation, and the evaluation as a "Japanese sword as an object of appreciation" drops significantly.

The Swordsmith's Material Philosophy: Between Technical Choice and Cultural Responsibility

For contemporary smiths, material selection is a matter of cultural and ethical judgment as much as, if not more than, a purely technical issue. Using tamahagane is an act that embodies identity as an "inheritor of traditional Japanese sword-making" and is also a social responsibility of certified smiths.

On the other hand, among young smiths and aspiring smiths, voices are heard saying "substantive understanding of forging technique is more important than material purism." They do not deny that there is a beauty of jihada that cannot be born without tamahagane, but the view is that basic forging techniques (fire-forging, quenching, and polishing) can be trained regardless of material.

The triangular relationship among smiths, materials, and tradition is one of the fundamental questions facing Japanese sword culture in the modern era. Maintaining a system whereby tamahagane is produced stably throughout the year and sufficient material is supplied to next-generation smiths is the practical task necessary to guarantee the cultural value of "tamahagane absolutism" for the future.