Roles in the Sword Forge: Teko, Utte, and Fuigo Operators in Traditional Swordsmithing

The Forge Works as a "Team"

When observing the forging of a Japanese sword from the outside, one imagines a single bladesmith (kaji) standing before the furnace, striking the steel repeatedly. However, in an actual traditional forge, multiple craftsmen and apprentices take on different roles and coordinate their work. It is physically and technically difficult for a bladesmith to create a sword in complete isolation.

The major roles in a forge can be broadly categorized into four: the bladesmith (master), the teко (te-ko), the uchiyaku (uchi-yaku), and the fuigoshi (fuigo-shi). Understanding how these roles function and how they are passed down is essential to understanding the manufacture of Japanese swords deeply.

Teко (Te-ko)—The Master's "Second Hand"

The teко is the assistant who holds the steel on the anvil (kanатoko) as the bladesmith works. The primary task is to grip the heated steel precisely with tongs (hasami-kane or kanshi), and to continuously move the material to the appropriate angle and position in time with the bladesmith's hammer strikes. Each time the bladesmith gives a signal—whether by eye contact or the way the hammer strikes—the teко instantly adjusts the steel's orientation. If this rhythm is lost, the precision of the forging drops significantly.

A skilled teко reaches the level of "reading the master's intent with the body," and the call-and-response breathing cultivated in the master-apprentice relationship determines the quality of the blade. In recent years, it is common for apprentices to serve as teко, though in the past some regions had specialized teко craftsmen. The work of teко is assigned early in an apprentice's training and offers an excellent opportunity to learn the master's hand movements up close.

Uchiyaku (Uchi-yaku)—The "Power Bearer" Who Assists with the Large Hammer

The uchiyaku is responsible for striking the steel while cooperating with the teко, using a large hammer (ootsuchi). While the bladesmith applies precise blows with a small hammer (kotzuchi), the uchiyaku handles larger deformations with the larger hammer.

Specifically, in the early stages of folding forging or during the susube (drawing out) phase, the uchiyaku's large hammer strikes the steel with greater force, extending it. Where the bladesmith indicates with the small hammer—"strike here"—the uchiyaku strikes firmly with the large hammer. Even slight timing misalignments can create uneven density or disruptive folds in the steel, so the uchiyaku requires not just physical strength but high concentration and the ability to synchronize with the master.

Today, many workshops have replaced the uchiyaku's work with power hammers, but traditional bladesmiths who maintain hand forging still entrust this role to their apprentices. Through the training of wielding the large hammer, apprentices can learn the "response of the steel" as a tactile sensation.

Fuigoshi (Fuigo-shi)—The Fire Master, Specialist in Controlling the Flame

The fuigoshi operates the fuigo (bellows)—the device that pumps air into the forge's furnace. In traditional forges, the bellows are operated by hand, so the technique of supplying air at the proper timing and intensity was essential.

The fuigoshi's greatest responsibility is temperature management of the furnace. In the forging of Japanese swords, it is essential to maintain the steel at an appropriate forging temperature (roughly 900–1300°C), but the furnace temperature is determined by the balance of three factors: the amount and type of charcoal and the air flow rate. The fuigoshi adjusts the air flow while observing the speed of the master's strikes and the color of the steel, constantly maintaining the optimal "state of the fire."

An experienced fuigoshi intuitively judges the temperature the steel "desires" from the color of the flames and the luminous color of the steel. This sensibility can only be acquired after standing before the furnace for many years, and it is a classic example of tacit knowledge that is difficult to teach in words.

Origins and Evolution of the Division of Labor System

The division of labor system in the forge has a history nearly as long as that of the Japanese sword itself. Large workshops in the Kamakura period are said to have achieved mass production through the collaboration of multiple swordsmiths and craftsmen, and it is believed that numerous apprentices and specialized assistants existed.

By the Edo period, a system centered on official court swordsmiths became established, and it became common to pair with apprentices and assistants provided by the clan to forge blades. The dramatic decline in demand for swords after the Meiji Restoration's abolition edict (1876) brought contraction to the forges, and the number of apprentices and assistants declined sharply. From the post-war revival period of swordsmiths onward, the standard form has become many swordsmiths working in "small workshops with one or two apprentices."

The Significance of Division of Labor in Technical Succession

The division of labor system is important not only for work efficiency but also from the perspective of technical succession. While serving as a teко and assisting the master's work, the apprentice observes up close the "movement of the master's hands," the "strength and weakness of strikes against the steel," and "the timing of folding," learning through the body. By actually wielding the large hammer as an uchiyaku, the apprentice imprints the "feel of the steel" into their own arms. By managing the furnace as a fuigoshi, they embodied knowledge of the "relationship between fire and steel."

Through such multifaceted learning processes, the apprentice eventually grows into a bladesmith capable of overseeing all processes. Division of labor is not mere efficiency—it is an educational mechanism for "learning the master's work from all angles."

Conclusion—Invisible Roles Support the Sword

A Japanese sword is not the work of a single bladesmith but the combined product of multiple roles working together in the forge. The teко, uchiyaku, and fuigoshi each support the master in their respective positions, and their accumulation determines the quality of a single blade. When visiting a modern bladesmith's workshop, one can feel the breath of this division of labor with one's own skin. If you wish to deepen your appreciation of Japanese swords, by all means take the opportunity to visit a forge demonstration and direct your attention to these "invisible roles."