Craftsman Collaboration in Completing a Single Koshirae: The Reality of Integrated Sword Mounting Production Involving Scabbard Makers, Lacquerers, Metal Workers, and Handle Wrappers

Koshirae is "The Art of Teamwork"

A Japanese sword consists of two parts: the blade (forged by the swordsmith) and the koshirae (the mounting). Koshirae refers to the entire exterior mounted on the blade and is composed of the following components.

• saya
• tsuka
• tsuba
• menuki
• fuchi-kashira
• seppa
• habaki

To complete a single mounting typically requires the collaboration of 4-6 different types of craftsmen. Each is an independent specialist, and together they adjust their techniques and aesthetic sensibilities to create a single work of art. This article uses the "uchigatana koshirae set" as an example to detail the processes and actual state of craftsman collaboration.

Process 1: Hakuginshi (Whitesmithing Craftsman) — Habaki and Seppa

After the blade leaves the swordsmith's hands and polishing by the polisher (togi-shi) is complete, the first mounting craftsman to appear is the "hakuginshi" (whitesmithing craftsman). This is a metalworking craftsman who produces the habaki and seppa.

The habaki is a metal fitting that secures the base of the blade and protects it from the koiguchi. It is precision work that accurately measures the blade's width at the base, the thickness of the spine, and the position of the machi, adjusting these to within 0.1mm.

• Materials include brass, red copper, silver, gold, and others (depending on the commission)
• Shapes include "double habaki," "yakiochi," and "nanako" (fish-roe pattern), among others

Seppa are thin metal plates that sandwich both sides of the tsuba, preventing looseness between the blade and the tsuba. Since habaki and seppa are always designed as a set, the hakuginshi becomes the first mounting craftsman to handle the blade.

Process 2: Tsuba Craftsman — The Metal Art That Defines Status

Next appears the tsuba craftsman. The tsuba has the greatest presence among sword fittings, and its shape and design vary greatly depending on the era, school, and purpose. Samurai's everyday swords typically featured practical iron tsubas (iron-ground melon or circular forms), while the formal swords of daimyo and high-ranking samurai used elaborate tsubas with red copper and gold inlays.

Modern tsuba craftsmen's work falls into two categories.

• "Coordination" — selecting and combining ready-made tsubas
• "Custom fabrication" — designing from scratch

For high-grade mountings, after considering the blade's balance, total weight, and the sword owner's preferences, the tsuba craftsman proposes the design and receives approval before beginning production. The popular openwork (sukashibori) tsuba can take over a month from initial sketch to completion.

Process 3: Menuki Craftsman — Minute Sculpting That Adorns the Hilt

Menuki are small metalworking sculptures embedded on the front and back of the tsuka. While they appear to be merely decorative, menuki originally served the practical purpose of concealing the hole for the mekugi that secures the nakago. Their shapes are diverse, including dragons, tigers, phoenixes, plants, and family crests, with the pair of front and back menuki indicating the sword owner's rank and taste.

Menuki craftsmen cast or forge metal and finish it using techniques such as hair-line carving (kebori), high relief carving (takabori), and color inlay (iroie). Today, it is common for tsuba and menuki craftsmen to work in both trades, but during the Edo period it was such a specialized craft that the renowned Goto family workshop, which specialized in the "mitsudokoro" (three-place ornaments) of menuki, kozuka, and kougai, served as the official craftsmen for the shogunate.

Process 4: Fuchi-Kashira Craftsman — Securing Both Ends of the Hilt

The fuchi is a metal ring that secures the end of the tsuka on the tsuba side, while the kashira is a metal cap that secures the tip of the tsuka. Materials include red copper, blackened iron, gold, silver, and alloys, with design unity with the menuki required.

The fuchi-kashira craftsman works with the menuki craftsman to realize an overall design program (for example, if the dragon is the main theme, dragon motifs are also incorporated into the fuchi's border). In modern times, craftsmen who handle fuchi-kashira, menuki, and kozuka as a set—working as "sword-fitting artisans"—are increasingly common.

Process 5: Saya-shi (Scabbard Craftsman) — The Wood-Working Specialist

Once the metal fittings' specifications are determined, the saya-shi takes precise measurements of the blade and manufactures the wooden scabbard (kizaya). The standard material for the scabbard is magnolia wood (hoooki), selected by discerning the grain, moisture content, and specific gravity. To avoid cracks that can develop from using partially dried wood, some swordsmiths use wood that has been dried for 3-10 years or more.

The saya-shi precisely molds the blade's length, width at the base, width at the tip, spine thickness, and curvature, creating a "split scabbard (kiriwari-zaya)" into which the blade fits perfectly. The precision of the koiguchi gap (0.1–0.2mm) achieves the balance of "easy to draw and difficult to fall out." There are only dozens of saya-shi throughout the country today, and chronic lack of successors is an issue.

Process 6: Nuri-shi (Lacquerer) — Protecting and Coloring with Lacquer Layers

Once the scabbard's wood base is complete, the lacquerer (nuri-shi) applies the lacquer finish. Representative techniques are as follows.

• Black lacquer (most common)
• Vermillion lacquer (shu-nuri)
• Abalone-shell lacquer (aoigai-nuri)
• Lusterless lacquer (roiro-nuri)

Lacquer is applied in multiple layers—primer, middle coat, and top coat—with each layer's drying requiring a high-humidity environment (urushi-buro). Completion takes a minimum of two weeks; high-quality pieces require 1-2 months. The scabbards of daimyo mountings sometimes have gold maki-e or mother-of-pearl inlay (raden) added, requiring collaboration with the maki-e craftsman in such cases.

Process 7: Tsuka-Maki-shi (Hilt-Wrapping Craftsman) — Tactile Sensation in the Hand

The tsuka-maki-shi glues ray skin (same-gawa) to the hilt wood (tsuka-gi), then wraps cordage (tsuka-ito) around it. There are differences depending on the school:

• Cord materials include silk, cotton, leather, and others
• Wrapping methods include diamond wrap (hishi-maki), double twist (moro-yori), itto-maki, and others

The wrapping method and tension are determined not only for visual beauty but also taking into account the tactile feel when gripped, resistance to slipping, and impact on the sword's center-of-gravity balance.

Koshirae-shi (Mounting Assembler) — The Coordinator Who Brings It All Together

There is a craftsman type called "koshirae-shi" who coordinates the multiple craftsmen mentioned above. The koshirae-shi primarily undertakes the following roles:

• Coordinating schedules among craftsmen
• Ensuring material consistency
• Serving as the single point of contact for customers

During the Edo period, daimyo-household mounting assemblers received bulk orders and distributed work to specialized craftsmen. Today, sword dealers and some craftsmen often take on the role of koshirae-shi.

The time required to complete a single mounting ranges from 2-3 months for standard pieces to over a year for high-quality custom work. When craftsmen working in different workshops finally integrate their efforts into a single sword—when the blade's radiance and the beauty of the mounting become one—that is where "Japanese craftsmanship as teamwork" is realized.