Kozuka and Kogai: The Utility and Artistry of Japanese Sword Side Tools

Utility and Art in Miniature

The kozuka (a small knife fitted into a pocket on the front of the koshirae) and kogai (a utility spike or hair-arranging tool on the reverse side) were everyday samurai implements that evolved into some of the finest examples of Japanese metalwork art.

History

The kozuka and kogai slots appear in tachi koshirae from the Heian and Kamakura periods. By the Azuchi-Momoyama and Edo eras, metalwork schools — especially the Goto family (17 generations), Nara Kinko masters, and Higo Kinko — competed to produce increasingly refined designs in shakudo, shibuichi, gold, and silver.

Notable Schools and Designs

The Goto family dominated high-prestige production for nearly three centuries, working auspicious motifs in gold high-relief on shakudo grounds. Nara kinko masters like Sugiura Joi and Tsuchiya Yasuchika pioneered realistic scenic and figural compositions in the 18th century, opening new artistic horizons.

Collecting

Kozuka and kogai by major schools can reach hundreds of thousands of yen even in isolation. They serve as an accessible entry point into kodogu collecting — smaller, more affordable, and appraised on their metalwork merit independently of any associated blade.