Tachi (inscribed Nagamitsu)

A Bizen Tachi Signed by Nagamitsu

The two characters cut into the tang read simply "Nagamitsu." They name one of the finest swordsmiths of medieval Japan, a man who worked in the village of Osafune in Bizen Province, today part of Setouchi City in Okayama Prefecture, during the closing decades of the thirteenth century. This tachi, a long curved sword once worn slung from the belt with its cutting edge facing down, the cavalry weapon that preceded the later katana, survives with its original tang intact and that short signature still legible after roughly 750 years.

The blade measures 72.9 centimetres along the cutting edge, with a curvature of 2.4 centimetres. The curve sits low, near the hilt, in the manner the Japanese call koshi-zori, and the body keeps its width well down toward the point, a feature swordsmiths describe as funbari. Held horizontally, the sword has the deep, archery-bow profile that marks the best Kamakura-period work.

It is held privately in Tokyo and is not on public display. What follows is an account of why a blade most people will never handle was judged worth protecting, and where its close relatives can be seen.

Nagamitsu and the Rise of Osafune

Bizen Province produced more swords than any other region of premodern Japan. The Yoshii River carried rich iron sand down from the hills, and generations of smiths settled along its banks. Among the schools that grew there, the one centred on Osafune came to dominate, and its rise began with two men: Mitsutada, regarded as the school's effective founder, and his son Nagamitsu.

Nagamitsu inherited his father's manner and pushed it further. Where earlier Bizen blades had leaned toward restraint, he and his contemporaries answered a warrior class increasingly engaged in real combat, giving their swords a generous curve that absorbed the shock of a cutting stroke. He is recorded with the court title Sakon-no-shogen, and a number of dated examples place his activity in the late thirteenth century, including a blade inscribed with a date corresponding to 1289. Scholars have long argued over the relationship between his plain two-character signatures and his longer titled ones, with some proposing two distinct smiths rather than one; the prevailing view treats them as the work of a single master. His surviving output is comparatively large and ranges beyond swords to include naginata and double-edged ken.

Under Nagamitsu the Osafune name eclipsed the older Ichimonji smiths and set the course for a tradition that would run for centuries. A large share of Japan's National Treasure swords are Bizen work, and Nagamitsu stands near the head of that lineage.

Reading the Blade

The Agency for Cultural Affairs designated this sword an Important Cultural Property on 29 August 1950. The reasons lie in the metal itself, recorded in the kind of close description that sword connoisseurs spend years learning to read.

The steel surface, the jigane, is forged in a fine ko-itame, a tight wood-grain pattern flecked with minute crystalline particles called ji-nie. Running through it is a faint, cloud-like reflection known as midare utsuri, a shadow of the temper pattern mirrored higher up the blade. This misty band is a signature trait of good Bizen work and is one of the first things a trained eye looks for.

The temper line, the hamon, is built mainly on choji, a pattern of overlapping shapes that resemble clove buds, here mixed with sharp, pointed peaks and varying in depth along the edge. The line is set in a deep, soft nioi, with brighter ko-nie scattered through it and frequent ashi, slender legs of hardened steel reaching toward the cutting edge. Bright streaks called kinsuji show most strongly from the working section of the blade up into the point. The temper in the point, the boshi, turns in a deep wave before rounding off with a small return. A single straight groove, a bo-hi, is carved into each face and runs out into the tang.

That tang is the clinching detail. It is ubu, meaning unshortened from its original form, finished with a chestnut-shaped end and file marks that slant in the katte-sagari pattern, pierced by a single peg-hole. Many swords of this age were cut down over the centuries to suit changing fashions of wear, often costing them their signatures. This one kept both its length and its mei, which is why the inscription can still be read as the smith left it.

Where to See Nagamitsu's Work Today

Because this blade is privately owned and not exhibited, the place to encounter Nagamitsu in person is the museum collection. The Tokyo National Museum in Ueno holds the most celebrated of all his swords, the National Treasure known as the Daihannya Nagamitsu. Slightly longer than the blade described here, at 73.6 centimetres, it carries the same plain two-character signature and a similarly vivid choji temper. Its name comes from a valuation of 600 strings of cash, linked in legend to the 600 volumes of the Great Wisdom Sutra. It passed through the hands of the Ashikaga shoguns, Oda Nobunaga, and Tokugawa Ieyasu before reaching the museum, and it appears in rotation in the Japanese sword gallery, Honkan Room 13. The museum holds a second tachi by Nagamitsu as well, once owned by the Ikeda lords of Inaba.

To understand the soil this sword grew from, travel to its birthplace. The Bizen Osafune Sword Museum in Setouchi City, Okayama Prefecture, stands on the ground where Nagamitsu worked. Around forty blades are shown at a time, rotated five times a year, and a working forge on the grounds gives demonstrations of traditional smithing, with smiths heating steel to around 1,200 degrees and hammering out sparks much as their predecessors did seven centuries ago. The museum opens from 9:00 to 17:00, with last admission at 16:30. It is a short taxi ride or a walk of under twenty minutes from Osafune or Kagato stations on the JR Ako Line.

Seeing a Nagamitsu in good light, the utsuri surfacing as you tilt the steel, is the closest most visitors will come to the blade catalogued here.