Sword (unsigned, Komihara Masahiro / Mitsutoku Gold Inlay

The Sword and Its Maker

The blade measures approximately 80.9 centimeters in cutting length, with a curvature of about 2.6 centimeters. By the standards of Japanese tachi, this is a remarkably long sword, and it is precisely this length that gave it the name "Ōmihara" — literally "Great Mihara." The blade is unsigned (mumei), as was common when older tachi were shortened in later eras, but at the time it was officially designated an Important Cultural Property in 1955 it was identified as the work of Masahiro, one of the leading smiths of the Ko-Mihara group.

The Ko-Mihara school flourished in the town of Mihara in Bingo Province from the closing decades of the Kamakura period through the Nanboku-chō era. Their style is often described as carrying a strong Yamato character — restrained, dignified, with refined straight temper lines (suguha) and finely worked steel surfaces — alongside subtle influences from the neighboring Bitchū tradition. On the Ōmihara blade, connoisseurs note a broad straight temper line interspersed with gentle waves and delicate "feet" of activity within the cutting edge, finished with a small rounded tip (komaru bōshi) and a particularly long, graceful curvature.

From Hideyoshi to the Asano Lords

The sword's recorded history begins in the late sixteenth century, when it formed part of Toyotomi Hideyoshi's personal collection of arms. After Hideyoshi's death in 1598, a grand ceremony was held at Maeda Toshiie's residence in Fushimi to distribute the late ruler's keepsakes among the daimyo. At this gathering, the long Mihara blade was presented to Asano Yukinaga, then lord of Wakayama in Kii Province and a son of one of Hideyoshi's most senior administrators.

Yukinaga assumed the court title of Kii no Kami in 1601, and it was after this that he commissioned the celebrated sword connoisseur Hon'ami Kōtoku to authenticate the blade and add a gold-inlaid inscription on the tang. The inlay reads, in essence: "Ōmihara — Futatsu-dō — received by Asano Kii no Kami — Hon'ami Kōtoku [signed with floral cipher]." The phrase "Futatsu-dō," meaning "two trunks," refers to a cutting test in which the blade was said to have severed two stacked bodies in a single stroke — a record of the sword's exceptional cutting performance, although the identity of the tester is not preserved.

When the Asano family was transferred to Aki Province to govern Hiroshima Domain in 1619, the sword traveled with them and remained one of the family's most prized heirlooms throughout the Edo period and well into modern times. It also earned a place in the early eighteenth-century catalog known as the Kyōhō Meibutsu Chō, a register of celebrated swords compiled for the eighth Tokugawa shogun. Notably, of all the Mihara school blades in existence, only this one was selected for inclusion — a striking testament to its standing among connoisseurs.

Why It Is Designated an Important Cultural Property

The Ōmihara was officially designated an Important Cultural Property of Japan on June 22, 1955. Its value rests on several intertwined grounds. First, as a work of swordsmithing, it represents the peak achievement of the Ko-Mihara school, exhibiting healthy steel, a restrained yet refined temper line, and a notably grand form rarely preserved at this length. Second, the gold-inlaid inscription by Hon'ami Kōtoku — one of the most influential sword authorities of the Momoyama and early Edo periods — provides a precious record of how leading experts of the time understood and authenticated the blade. Third, its documented passage from Hideyoshi to the Asano family makes it one of the very few swords whose ownership history is traceable in such fine detail across more than four centuries.

Highlights for Visitors

Although swords are rotated in and out of display to protect them from light and humidity, when the Ōmihara is exhibited at the Tokyo National Museum it is typically shown in the Japanese Sword room of the Honkan (Main Building), where blades are presented in low-lit cases that allow visitors to study their geometry and surface activity in detail.

Several aspects reward close attention. The first is sheer scale: at over 80 centimeters, the blade communicates the imposing presence a long tachi would have had on the battlefield or worn slung at the hip in formal warrior dress. The second is the gentle, deep curvature, which is more pronounced than on many tachi of the period and lends the blade a particularly elegant silhouette. Third, the gold-inlaid characters on the tang, though small, are an intimate point of contact with the hand of Hon'ami Kōtoku himself and the moment around 1601 when the sword was formally renamed and recorded.

Around the Museum

The Tokyo National Museum stands within Ueno Park, one of Tokyo's most rewarding cultural districts, and a visit to see the Ōmihara can easily be combined with an extended day of museum-going and nature walking. The park itself is famous for its cherry blossoms in early April and its rich autumn colors in November.

Nearby attractions of interest include:

• The National Museum of Nature and Science, just south of the Tokyo National Museum within Ueno Park.
• The Tokyo Metropolitan Art Museum, hosting major exhibitions of Japanese and international art.
• The National Museum of Western Art, designed by Le Corbusier and inscribed on the UNESCO World Heritage List.
• Ueno Tōshō-gū, a richly decorated Edo-period shrine dedicated to Tokugawa Ieyasu.
• Shinobazu Pond and Bentendō, a peaceful temple set on an island in the lotus-covered pond.
• The lively Ameya-Yokochō shopping street just outside Ueno Station, ideal for a casual lunch.

Travelers especially fascinated by Japanese swords may also wish to visit the Japanese Sword Museum (Tōken Hakubutsukan) in Sumida Ward, located near the Ryōgoku Kokugikan sumo arena, where blades from across the country are exhibited in dedicated galleries.