Lacquering Techniques of Shayashi: Processes and Material Selection for Roiro Urushi, Ishime Coating, and Togidashi Maki-e on Japanese Sword Scabbards

The Role of Lacquer in Saya-shi Work

The saya (scabbard) of a Japanese sword is not merely a "storage case for the blade." The saya protects the sword, ensures proper appearance when worn, and is an essential element that constitutes the overall artistic value of the blade. The lacquer (urushi) that covers the surface of the saya is a process where the saya-shi's skill is tested most rigorously in both durability and aesthetics.

The work of a saya-shi can be broadly divided into two parts: "wood base work (woodworking process)" and "lacquer coating process." While wood base work is the fundamental process that determines the shape of the saya, it is no exaggeration to say that the final impression of the saya is determined by the lacquer coating. This article focuses on the lacquer coating techniques of the saya-shi and explains the details of the process and materials involved.

Lacquer coating is not a one-step process but rather an accumulation of repeated cycles of coating, drying, and polishing. Lacquer has the property that it only hardens in a humid environment, so the saya-shi advances the work by slowly drying each layer in a specialized drying shelf called a "urushi-buro" (lacquer chamber) that maintains humidity. If the next coat is applied before one layer has fully dried, internal distortion can result, later causing surface shrinkage or cracking. Careful, step-by-step completion without rushing is an absolute requirement for quality scabbard lacquer.

Types of Lacquer Used on Scabbards

There are several types of lacquer coating applied to scabbards, each with different uses and levels of difficulty.

Roiro coating (roiro-nuri): Considered the most elegant coating method, this technique involves applying multiple layers of black lacquer and then polishing it with charcoal powder (sumiko) to create a deep, mirror-like gloss with transparency. The name "roiro" refers to this distinctive deep black luster. It is often used on the scabbards of formal swords used by samurai of high rank, and in modern times is applied to the finest fittings. The polishing process can take dozens of hours, making it the most time- and skill-intensive coating method.

Ishime coating (ishime-nuri): A technique where fine surface irregularities are created on lacquered surfaces using rapeseed (natane) particles or special tools, creating a distinctive texture resembling stone. It resists slipping even when fingers are sweaty and was commonly used on practical fittings. It was one of the preferred coating methods for samurai during the Edo period when actually wearing swords, and was available in various colors including black, red, and brown.

Roiro nashiji coating (roiro nashiji-nuri): A technique that creates a fine, pear-skin-like textured surface by applying roiro finish over a "nashiji" base created by spraying lacquer mixed with gold or silver powder. It has a luxurious quality and often requires collaboration with makie artists.

Each coating differs not only in final appearance but also in practical aspects such as texture and slip resistance when held. Depending on the overall formality of the fittings and the context of use (ceremonial or practical), the saya-shi typically consults with the client when determining which coating method to apply.

The Process of Togi-dashi Makie: Collaboration Between Saya-shi and Makie Artists

The most intricate lacquer work on scabbards is known as "togi-dashi makie" (polished-out gold painting). This technique cannot be completed by a saya-shi alone and requires collaboration with a makie artist.

The process outline is as follows. First, the saya-shi finishes the wood base and applies an undercoat of lacquer (shitaji-urushi). Next, the makie artist uses gold powder, silver powder, and colored powders to draw the design and fixes it with lacquer. After the makie dries, layers of transparent lacquer (suki-urushi) or roiro lacquer are applied over it to bury the makie design beneath the lacquer. Finally, the surface is polished out with charcoal and abrasives, causing the buried makie design to emerge from beneath the lacquer.

Scabbards created with this technique have a unique depth: the surface is completely smooth while the design floats within the lacquer. Auspicious patterns such as aoi crests, paulownia crests, and pine-bamboo-plum, along with natural patterns such as landscape, waves, and cranes and turtles, were commonly used.

The polishing process is a task with no room for error: over-polishing risks removing the design itself, while insufficient polishing leaves the design hidden beneath the lacquer. The saya-shi (or makie artist) relies solely on fingertip sensation to judge the depth of polishing, and this discernment is the key measure of skill in togi-dashi makie.

The Importance of Undercoating: Hemp Cloth Layering and Ground Rust Stabilization

To create high-quality lacquered scabbards, "undercoating" before beginning the painting process is critically important. Inadequate undercoating can cause lacquer to crack or peel.

Hemp cloth layering (asa-nuno-zumi): The process of attaching hemp cloth to the wood base using lacquer. This prevents lacquer from cracking due to wood movement (expansion and contraction) and is especially used in areas prone to cracking, such as corners and curved sections.

Ground rust stabilization (jisabi-katame): The process of applying "ground rust lacquer (jisabi-urushi)" made by mixing iron powder or charcoal powder into lacquer to smooth out irregularities. Multiple coatings create a smooth undercoat. This requires alternating work with sanding (shitaji-yogi), and even experienced saya-shi can spend weeks on the undercoating alone.

Although undercoating is invisible once complete, much of the durability of the scabbard is determined at this stage. Omitting or simplifying undercoating can result in lacquer surface shrinkage and peeling appearing over the course of years or decades, despite the finished appearance. Therefore, the amount of effort invested in undercoating is a major indicator of the care taken in the saya-shi's work.

Red Lacquer (Shu-urushi) and Alternative Coating Techniques

Not only black lacquer but also scabbards using red lacquer (shu-urushi, including cinnabar and mercury red) are common. Red scabbards are frequently seen on swords dedicated to shrines and on women's concealed swords and short swords, characterized by vivid coloring. While synthetic red (iron sulfide-based) is used in modern times, traditional cinnabar red has deep color and exceptional beauty.

Many other special techniques collectively called "alternative coatings (kawari-nuri)" also exist, such as spiral coating, flowing coating, and brush-mark coating, which add expression to the lacquer. These have varied in popularity across different periods, with the saya-shi selecting them to match the client's preferences and the overall design of the sword.

Basic Care and Storage After Completion

After hardening, lacquered scabbards continue to be affected by their environment like living things breathe, so daily handling affects their lifespan.

• Prolonged exposure to direct sunlight or strong lighting can alter the lacquer's luster and color, so store in a shaded location.
• Extremely dry environments and excessively humid environments are both unfavorable for lacquer. Avoid rapid temperature and humidity changes, and store in a stable indoor location whenever possible.
• When inserting or removing the blade from the saya, handle carefully without rubbing the koiguchi or the interior of the saya vigorously. Applying excessive force can cause chips or cracks in the lacquer surface.
• Remove sweat and oils from hands by gently wiping with a dry, soft cloth; do not wipe with solvents or alcohol-containing liquids. These can damage the lacquer surface.

Daily care is based on the principle of "touching less and wiping less," and it is important to remember that excessive maintenance can actually damage the lacquer.

Modern Saya-shi and the Transmission of Lacquer Coating Techniques

Even in modern times, the number of saya-shi is small, and among them, craftspeople who undertake serious lacquer work are even fewer. The transmission of high-quality sword fittings culture requires the coordination of multiple craftspeople—saya-shi, lacquer artisans, and makie artists—and maintaining this network is itself a challenge.

In cultural heritage restoration, saya-shi are required to analyze the lacquer of old fittings and restore them as closely as possible to their original materials and methods. Combining knowledge of traditional techniques with modern analytical technology is one of the roles expected of contemporary saya-shi.

The lacquer on a scabbard continues to harden and stabilize slowly over decades after completion. High-quality lacquered scabbards retain their luster even a hundred years later, truly exemplifying "craftsmanship that reaches completion over time."

When selecting a sword with fittings, in addition to checking the condition of the blade itself, it is prudent to verify that the scabbard's lacquer shows no large chips, lifting, or deep cracks. When an appraisal document is included, comparing the information contained within to the actual condition of the object while viewing it will deepen your understanding of the saya-shi's workmanship.