Tachi〈Inscribed by Bizen Kuninaga Funaju Sakon General

Tachi by Nagamitsu: A Kamakura-Period Masterpiece of the Bizen Osafune School

Among the vast treasury of Japanese National Treasures, few objects embody the artistry and martial spirit of medieval Japan as vividly as a finely forged tachi. The Tachi, signed "Bizen no Kuni Osafune-jū Sakon Shōgen Nagamitsu tsukuru" (太刀〈銘備前国長船住左近将監長光造〉), is one such masterpiece—a long sword crafted during the Kamakura period (1185–1333) by the celebrated swordsmith Nagamitsu. Housed at the Hayashibara Museum of Art in Okayama City, this blade stands as a testament to the extraordinary skill of the Osafune school and the enduring beauty of Japanese sword craftsmanship.

The Swordsmith Nagamitsu and the Osafune Legacy

Nagamitsu was the second-generation head of the Osafune school, one of the most prolific and influential lineages of swordsmiths in Japanese history. His father, Mitsutada, founded the school in the town of Osafune in Bizen Province—present-day Setouchi City, Okayama Prefecture—an area blessed with abundant high-quality iron sand and charcoal, ideal for sword production.

Nagamitsu is believed to have been active from around the Bun'ei era (1264) through the Kagen era (1304). He ranks first among all Japanese swordsmiths in the number of signed masterpieces that survive to the present day, with approximately 150 known inscribed works. Of these, six have been designated National Treasures and at least 28 are classified as Important Cultural Properties—an unmatched record that speaks to both his extraordinary output and the exceptional quality maintained throughout his career.

The inscription on this particular tachi includes the title "Sakon Shōgen" (左近将監), an honorary court rank that Nagamitsu bore. Blades bearing this fuller signature are relatively rare among his works, making this sword an especially prized example of his craftsmanship.

Physical Characteristics and Artistic Merit

This tachi exemplifies the classic form of a Kamakura-period long sword. It features a shinogi-zukuri construction with an iori-mune ridge, a blade length (nagasa) of approximately 74.8 centimeters, and a curvature (sori) of about 2.5 centimeters. The pronounced koshi-zori (curvature near the base) and medium-sized kissaki (point) are characteristic of swords from this era.

The steel surface (jigane) displays a fine and tightly forged ko-itame hada (small wood-grain pattern) interspersed with delicate ji-nie (crystalline particles), while a shimmering midare-utsuri (irregular reflection pattern) adds depth and visual complexity to the blade.

The hamon (temper line) is the true highlight of this sword. It features a vibrant chū-chōji (medium clove-blossom pattern) mixed with gunome (undulating waves) and ko-midare (small irregular patterns). The nioi (misty glow along the hamon) is deep and luminous, with areas of ko-nie (fine crystalline particles) and kinsuji (golden lines) adding further refinement. This style of elaborate, floral temper pattern is the hallmark of the Osafune school and Nagamitsu in particular.

Why This Sword Was Designated a National Treasure

This tachi was first designated as an Important Cultural Property (then called Important Art Object) on June 26, 1942, and subsequently elevated to National Treasure status on February 19, 1957. Several factors contributed to this prestigious designation:

• It bears the rare full-length signature of Nagamitsu, including his court title "Sakon Shōgen," providing invaluable historical documentation of the smith and his era.
• The blade demonstrates exceptional craftsmanship in both the forging of the steel and the creation of the temper pattern, representing the pinnacle of the Osafune school's artistry.
• The sword is remarkably well-preserved for its age of over 700 years, with the jigane and hamon retaining their original brilliance and clarity.
• It serves as a key reference point for understanding the evolution of Nagamitsu's work and, by extension, the development of the entire Osafune tradition.

Highlights and What to Look For

When viewing this tachi, pay special attention to the following features:

The hamon is the most striking element. The chōji pattern resembles a field of clove blossoms in full bloom, with each "petal" of the temper line varying subtly in shape and height. This dynamic, almost painterly quality in steel is what elevates the finest Japanese swords to the realm of art.

The midare-utsuri is another remarkable feature. This shadowy reflection pattern appears on the flat of the blade, mirroring the undulations of the hamon in a softer, ghostly form. Achieving this effect requires precise control of temperature and technique during the hardening process—a skill that was largely lost after the medieval period.

The inscription itself is also noteworthy. The characters are boldly and confidently carved, and the inclusion of Nagamitsu's full title and place of residence provides a wealth of historical information in a few elegant strokes of the chisel.

The Hayashibara Museum of Art

The Hayashibara Museum of Art, founded in 1964, was the first art museum to open in Okayama City. It stands on the site of the former Ninomaru reception hall (taimenjo) of Okayama Castle, in a serene setting surrounded by greenery with views of the castle's golden shachihoko-topped tower.

The museum's building was designed by Kunio Maekawa, one of Japan's most celebrated modern architects and a student of Le Corbusier. It was his first museum project, and the flowing, single-route exhibition plan echoes the design philosophy of the National Museum of Western Art in Tokyo.

The collection encompasses approximately 9,000 items, including 3 National Treasures and 26 Important Cultural Properties. Highlights include swords, samurai armor, Noh theater costumes, lacquerware, paintings, and calligraphy inherited from both the Hayashibara family collection and the former Okayama feudal lord Ikeda clan. The museum does not maintain a permanent exhibition; instead, it presents 4–5 curated exhibitions and 1–2 special exhibitions annually, rotating works from its vast holdings.

Please note that the National Treasure tachi is not always on display. It is shown during selected exhibitions, so visitors are advised to check the museum's official website or contact the museum in advance.

Exploring the Surroundings

The Hayashibara Museum of Art is ideally situated within Okayama's cultural heartland, making it easy to combine a visit with several other notable attractions.

Okayama Castle, known as "Crow Castle" for its striking black exterior, stands just east of the museum and offers panoramic views from its reconstructed main tower. Across the Asahi River lies Korakuen Garden, one of Japan's three most celebrated landscape gardens, where visitors can stroll through meticulously maintained lawns, groves, and tea houses.

For those with a deeper interest in Japanese swords, the Bizen Osafune Sword Museum in nearby Setouchi City is approximately 40 minutes east by car. Located in the historic heart of Japan's greatest sword-producing region, the museum offers demonstrations of traditional sword forging and displays of blades spanning centuries of Bizen craftsmanship.

Okayama is also a convenient gateway to other cultural destinations in the region, including Kurashiki's Bikan Historical Quarter, with its picturesque canal-side warehouses and the renowned Ohara Museum of Art, about 20 minutes west by train.