The Kogai Guide: From Heian Origins to Higo Metalwork's Four Schools—Your Gateway to Sword Fittings Collecting

What is Kogai—A Unique Presence Among Japanese Sword Fittings

Kogai is a slender metal implement inserted into a specialized groove in the saya of a Japanese sword (called the kogai-bi), originally said to have been used for grooming the hair. It is typically 20-22 cm in length and 1-2 cm in width, with a distinctive shape that widens at one end.

Among sword fittings, the tsuba, menuki, and fuchi-kashira are relatively well-known, but kogai is a prime example of something whose name many people don't know. However, kogai is an important element that completes the koshirae of a Japanese sword, and Edo-period metalworkers poured their highest techniques into the design of kogai.

The Historical Origins of Kogai—From Heian Period Aristocratic Culture to the Samurai Class

The prototype of kogai is found in hair ornaments used by Heian period court women. Kogai from this era were mostly made of wood or ivory, with metal versions being a symbol of noble status. From the Kamakura period onward, as the samurai class rose to power, kogai became incorporated into weaponry as a practical tool.

There are various theories about the uses of kogai among the samurai: in addition to the theory that it was a tool for tying up hair, there are theories that it was used as an ear pick and as a tool for fine work such as undoing seams. In any case, it was a practical item carried daily and also something "to display" as part of the sword mounting, so great care was taken with its design.

Combination with Kozuka—"The Three Small Implements of Uchigatana Koshirae"

In the koshirae of an uchigatana, it is considered proper to have three types: kogai, kozuka, and menuki. Kozuka is a small blade (blade length approximately 10 cm) inserted in the saya, used for multiple purposes such as cutting paper, severing rope, and eating. Kogai and kozuka were typically made as a pair by the same metalworker, and coordinating their designs was the proper etiquette.

In the sword fitting market from the late Muromachi through early Edo period, which was dominated by the Gotō family, the combination of kogai, kozuka, and menuki carved in "Gotō family style" became established as the "standard highest quality" for samurai. The seventeen generations of the Gotō family, beginning with Gotō Yūjō, continued as official suppliers to the shogun's household until the end of the Edo period, and extant kogai and kozuka made by the Gotō family are valued as the highest examples of metalworking art.

Edo Metalworking Techniques—Techniques That Adorn Kogai Design

The techniques used by Edo-period metalworkers in the creation of kogai were diverse.

Nikubori (relief carving): A technique of carving the metal surface three-dimensionally to make the pattern stand out. Classical designs favored by the Gotō family, such as "sparrows on bamboo grass" and "nightingales on plum," were often expressed through nikubori.

Zougan (inlay): A technique of inlaying silver and akagane into a gold ground. The combination of multiple materials, such as expressing leaf veins with gold line inlay on a shibuichi (silver-copper alloy) base, enriches the expression of kogai.

Nanako-uchi (fish roe ground): A technique of striking fine dots evenly into the background metal. The regular arrangement of tiny fish-roe-like dots creates an effect that enhances the pattern placed upon it. It is also a technique favored by Higo metalworkers.

Higo Metalworking Kogai—An Austere Aesthetic

The kogai produced by Higo metalworkers from Higo (Kumamoto) possess a concise and powerful aesthetic in contrast to that of the Gotō family. Higo metalworkers, represented by the four schools of Hayashi, Nishigaki, Hirata, and Shimizu, also produced kogai as part of their distinctive aesthetic "Higo koshirae" established from the mid-Edo period onward.

The Higo metalworkers' kogai, which minimizes ornamentation and derives meaning from only minimal openwork and a small amount of gold and silver inlay on an iron ground, embodies the "aesthetic of subtraction" that accords with the sensibility of chanoyu (tea ceremony).

Extant Masterpieces and Points of Appreciation

Among the notable examples of kogai transmitted to the present day, representative works include a peony-design kogai made by the Gotō family, an iron-worked kogai made by the Higo metalworker Hayashi Matashichiro, and a fierce tiger-design kogai made by the Edo master Yokoya Sōmin.

When appreciating kogai, appreciation deepens by keeping three points in mind: ① the theme of the design (auspicious pattern, samurai cultural motif, or literati preference), ② materials and techniques (metal color tone, precision of inlay, depth of carving), and ③ stylistic unity with the paired kozuka.

Among sword fittings, kogai are relatively easy to obtain and serve as an appropriate entry point for beginning collectors to experience the refinement of metalworking.