The Sayashi's Craft: Techniques and Materials of Shirasaya and Koshirae Scabbards

The Role of the Saya-shi Craftsman

When discussing Japanese swords, attention tends to focus on the blade itself, but the "saya" (scabbard) that holds and protects the sword is also an essential element of sword culture. Craftspeople who specialize in making sayas are called "saya-shi." The work of a saya-shi encompasses both the functional aspect—safely storing, transporting, and carrying the sword—and the decorative aspect as a work of art and craft.

A saya-shi is a type of woodworker, but possesses advanced specialized technical skills distinct from general woodworkers or furniture makers. The saya must fit the blade perfectly without the slightest discrepancy, requiring precision work that matches the blade's curve, width, and thickness. In modern times, the number of saya-shi is extremely small, and the transmission of their technique has become an issue.

The manufacture of Japanese swords is not completed by the swordsmith alone. The togishi who sharpens the blade, the shiroganeshi who makes fittings like the habaki, and the saya-shi who makes the scabbard each bring their specialized techniques to complete a single sword. When commissioning a complete set (koshirae), additional craftspeople become involved: the tsuka-maki-shi who wraps cord and leather around the grip, the nuri-shi who applies lacquer to the scabbard and tsuba, and the makie-shi who applies makie. The saya-shi is one of the craftspeople working at the closest distance to the blade in this system of specialized labor, and bears the responsibility of making a final assessment of the condition of the blade after other craftspeople have finished their work.

Differences Between Shirasaya and Koshirae-saya

There are roughly two types of sayas made by saya-shi: "shirasaya" and "koshirae-saya."

Shirasaya is a simple scabbard made from magnolia wood, without lacquer or decoration. Its primary purpose is for storing and preserving the sword, and is also called a "preservation scabbard." The shirasaya is currently the most basic form of sword storage and preservation, with the majority of important swords held in museums, art galleries, and private collections housed in shirasaya.

A practical scabbard designed for carrying the sword is the "koshirae-saya." It is decorated with various techniques including lacquer painting, makie, and shell inlay, and combines with sword fittings such as the tsuba, tsuka, and menuki to form a "koshirae" (complete sword set). The koshirae-saya is what samurai actually wore at their side, with styles varying by era, school, and the rank of the user.

The table below summarizes the main differences between shirasaya and koshirae-saya.

Because shirasaya and koshirae-saya differ in purpose and structure, the saya-shi possesses the technique to adapt their methods from wood selection through finishing according to the client's needs.

Manufacturing Process of Shirasaya

The core of a saya-shi's work is the production of precision shirasaya. Let us examine the process step by step.

Wood Selection and Drying: The primary material for sayas is magnolia wood (hoo-no-ki). Magnolia is soft and easy to work with, while possessing a certain strength and good lacquer absorption. Uniform grain and resistance to splitting are also important selection criteria. The wood must be thoroughly dried before use and stabilized to prevent warping. If green wood or incompletely dried material is used, the scabbard will eventually warp and create gaps between itself and the blade.

Wood Cutting and Pattern Taking: The dried magnolia board is roughly shaped to match the width and length of the blade. The blade itself is placed against the wood to take a pattern, and the wood is carved to fit perfectly.

Splitting in Half and Carving the Blade Cavity: The wood is split lengthwise into two halves, and a cavity (blade cavity) to accommodate the blade is carved into the inside of each half. This work represents the core of the saya-shi's technique. The gap between blade and scabbard must be minimized. If the gap is too large, the blade may move and become damaged; conversely, if the gap is too small, the sword cannot be drawn or sheathed. Through repeated fine adjustments, the blade cavity is finished so the blade slides in smoothly.

Joining and Gluing: Once the carving is complete, the two halves of wood are joined together and bonded with specialized adhesive (such as rice-based paste or other natural adhesives). This step requires the seam to be beautifully finished and inconspicuous.

Shaping the Exterior and Final Finish: After the adhesive dries, the exterior shape is refined. The curve, width, and thickness are balanced, and the scabbard is finished with a smooth texture and contours that follow the shape of the sword. The surface is polished smooth to completion.

Tools Used by Saya-shi

The work of a saya-shi centers on hand tools rather than power tools. When carving the blade cavity, small knives and chisels honed for specific purposes are used, carefully removing material while observing the wood's hardness and grain. Sharpening the blades to maintain their cutting edge is also an important task performed by the saya-shi, and rather than using factory-made tools as-is, the saya-shi adjusts and adapts tools to their hand, using them over a long period. This very approach to tools becomes part of the saya-shi's technique. Carving the blade cavity often relies not only on sight but also on the sensitivity of the fingertips, with the precision of the finished work being determined by experience-honed sensation.

Wood Selection and Material Knowledge

For a saya-shi, knowledge of wood is fundamental to their craft. Magnolia has become the established primary material because, as mentioned above, it offers an excellent balance of workability, strength, and compatibility with lacquer, though other woods may be selected depending on the application.

For koshirae-saya, harder woods than magnolia (such as cherry or maple) are sometimes used as a base for lacquer finishing. For special commissions, rare woods such as ebony or rosewood are occasionally used, though these are difficult to work with and command higher prices.

Saya-shi are constantly attentive to securing high-quality magnolia material and treasure their long-standing relationships with wood suppliers and lumber merchants. Discernment based on experience is required—assessing wood grain flow, the presence or absence of knots, and moisture content.

The Role of Shirasaya and Storage Methods

The reason shirasaya are so highly valued lies in their simplicity, with decoration stripped away. While lacquered koshirae-saya are beautiful, moisture tends to accumulate inside them, and if a blade is left within one for an extended period, rust can result. In contrast, shirasaya, with their wood surface that readily absorbs and releases moisture without coating or painting, are said to maintain the blade in a relatively stable environment. For this reason, when storing a sword as an artwork for an extended period, it is common practice to commission a separate shirasaya and house the blade within it, apart from any decorative koshirae.

During storage, it is advisable to avoid direct sunlight and high heat and humidity, placing the scabbard horizontally in a well-ventilated location. Since the shirasaya itself is made of wood, repeated extreme drying or humidity fluctuations can cause warping or gaps to develop over time. Periodically checking how the blade sits in the scabbard and, if something seems amiss, consulting with a saya-shi about adjustment or remake is one way to maintain a sword in good condition.

The Current Situation of Modern Saya-shi

Currently, the number of active saya-shi in Japan is extremely small, with exact numbers not documented, though estimated to be in the dozens. Like sword smiths (state-certified swordmakers, with whom the Cultural Agency's guidance results in a practical standard of approximately 24 blades per year, though there is no legal limit on numbers), saya-shi also acquire their skills through apprenticeship, though institutional support is limited.

Successor cultivation programs are conducted with the support of the All Japan Sword Dealers Cooperative and the Cultural Agency, but due to income instability and difficulty in life planning, few young people enter the profession. As experienced saya-shi age, recording and passing down their techniques has become urgent.

On the other hand, as interest in Japanese swords grows, young people interested in becoming saya-shi are gradually appearing. The typical career path involves apprenticing under a master as an assistant and, after years to over a decade of training, becoming independent. Commissions for shirasaya production from overseas sword enthusiasts have increased, creating opportunities for saya-shi techniques to be internationally recognized.

Commissions for saya-shi work are typically made through sword dealers and shops, with opportunities for individuals to directly contract with a saya-shi being limited. Those who own authentic swords should periodically check the condition of the shirasaya housing them, and if they notice concerns such as gaps or looseness, considering consultation with a saya-shi through their dealer is a way to enjoy their swords in good condition for years to come.