The God of Iron-Making—What is Kanayago-kami?

The most widely worshipped protective deity of iron-making and forging in Japan is "Kanayago-kami (金屋子神)". This deity has its main shrine at Kanayago Shrine (金屋子神社) in Yasugi, Shimane Prefecture, and has been deeply revered by tatara smelters (iron-makers, kanashi) and blacksmiths throughout the Chugoku Mountains.

There are multiple legends about the origin of Kanayago-kami, but the most widely told is the theory that she is "a goddess who descended from Takama-ga-hara". According to Shimane legend, a deity who carried iron-making techniques traveled from place to place, ultimately descending upon the Yasugi area and bestowing upon the local people the knowledge of iron-sand collection, tatara smelting, and forging.

The core of this legend is "the sacralization of iron-making technology". Tatara smelting was understood as a technique bestowed by the deity, and those engaged in iron-making and forging developed a consciousness of performing their craft under a covenant with the divine. This concept became the foundation for the numerous religious rites, taboos, and rituals observed by blacksmiths.

Tatara Smelting and the System of Religious Rites

Tatara smelting in the Chugoku Mountains was conducted not merely as an industrial activity, but as a religious practice integrated with Shinto ritual. At the start of operations, there was always a ritual reporting to the deity and prayer (operational prayer festival), and a sacred shelf was established at the center of the furnace (takado), where a sacred tablet of Kanayago-kami was enshrined.

A representative religious rite is the "Chinkaasai (fire-calming festival)". This was a prayer for protection from fire disasters related to the dangerous work of handling smelting fires, and was performed by inviting a Shinto priest before the start of operations. During operations, the concept that the furnace fire was "the deity's fire" was maintained, and anything impure was strictly forbidden from approaching the furnace.

Particularly noteworthy is the custom of "forbidding women". Women were forbidden from entering the tatara smelting site. This was based on the belief that Kanayago-kami is a female deity who dislikes the presence of other women. This taboo was gradually lifted after modernization, but some smelting works maintained it informally even into the 20th century.

Pre-forging Religious Rites of Swordsmiths—The Prayers of Sword Makers

Swordsmiths (toshin) who received tamahagane from tatara smelters and forged swords also maintained their own system of religious rites. The form of religious rites observed by swordsmiths varied by region and family lineage, but the common elements can be summarized as follows.

Purification before forging: Before forging important swords—blades for dedication to daimyo, shrines, or temples, or blades aimed at becoming masterpieces—the swordsmith would purify himself. This practice, called saikai mokuyoku (purification through abstinence and bathing), required maintaining physical cleanliness through dietary restrictions (avoiding meat), bathing, and keeping clothes clean.

Sacred shelf at the furnace: A sacred shelf was always established in the forge (kajiba), where Kanayago-kami or Inari-kami (in some regions, Inari is considered the protective deity of forging) was enshrined. The custom was to offer prayers before starting work and to report after completing it.

Selection of auspicious days: The dates for beginning to forge and for important processes (hardening, application of clay pattern) were chosen by consulting the calendar for auspicious days. Particularly for hardening, which is a "one-chance" process, the auspiciousness of the day was considered along with weather, temperature, and water temperature.

Taboos in the forge: There were customs against certain words in the forge. Based on a belief in the power of words, inauspicious words such as "death" and "breaking" were avoided, and a custom of using auspicious words instead remained in various places. Additionally, the practice of forbidding menstruating women from approaching the forge was widely observed in connection with Kanayago-kami worship.

Faith Inherited by Modern Swordsmiths

To what extent do modern swordsmiths observe the above religious rites? Referring to interview records of Living National Treasures and unscreened swordsmiths, as well as works by swordsmiths themselves, while there is individual variation, many swordsmiths continue to practice some form of religious rites, purification, and taboos.

Miyairi Yukihira (1913–1977) was a renowned swordsmith from Nagano who is said to have maintained devout Shinto faith throughout his life, never neglecting the careful selection of tamahagane, purification before forging, and gratitude to the furnace. Through Miyairi's master-apprentice relationships, this spiritual attitude has been transmitted to later generations.

What many modern swordsmiths speak of is the interpretation that "religious rites are not superstition, but a means of spiritual concentration." Praying before hardening functions as a psychological ritual that reaffirms the gravity of the work and heightens concentration. Operating in a separate dimension from scientific rationality, it contributes to the spiritual stability of the craftsman.

Furthermore, at Nippon Toshin Tatara (the tatara smeltery in Okuizumo, Shimane Prefecture, which operates once a year and supplies tamahagane), operational festivals with priests invited from Kanayago Shrine continue to be held in the present day. The deliberate incorporation of Shinto ritual into the traditional iron-making revival project reflects the Japanese sword industry's stance of viewing technical transmission and transmission of spiritual culture as inseparable.

The God of Forging and the Soul of the Blade—The Sacred Nature Pervading Japanese Swords

Behind the reverence for Japanese swords as "beings in which spirits dwell," transcending mere weapons or artworks, lies this Shinto and religious context. The blades forged by swordsmiths who prayed to the deity, handled fire with a purified body, and worked under the gaze of sacred shelves have their entire creation process sanctified.

Behind the treatment of blades dedicated to shrines, blades treasured as family heirlooms, and blades that witnessed samurai seppuku—all as "special beings"—lay a deeply rooted cultural notion of the sacred nature of swords. Even in the present day, this concept of sacredness continues to live on in the form of "reverence for swords" among sword collectors and connoisseurs.