Tachi (named Yasuie)

Tachi Signed "Yasuie": The One Sure Blade of a Vanished Smith

Two shallow characters cut into the iron of the tang carry almost the entire historical weight of this sword. They read 安家, Yasuie, and they sit on the hakiomote (the side facing outward when the blade hangs edge-down from the belt), just below where the habaki collar once gripped the blade, set close to the back ridge. Plenty of Heian swordsmiths are names without surviving work, or surviving work without names. Yasuie is the rare case where one blade, this one, is accepted without serious doubt as his.

The sword is a tachi, the long, deeply curved slung sword that a mounted warrior wore edge-down. Its blade measures 77.3 centimeters with a curvature of 3.2 centimeters, and the curve concentrates low, near the hand, in the manner sword scholars call koshi-zori. The point is small, the body tapers noticeably from base to tip, and the steel has never been shortened or re-tanged. What you see is close to what left the forge, somewhere in western Japan, late in the Heian period.

It belongs to the National Institutes for Cultural Heritage and is kept at the Kyoto National Museum.

A Smith on the Edge of the Record

Yasuie is usually placed in the orbit of Yasutsuna of Hōki Province, the smith credited with some of the earliest curved Japanese blades and remembered today chiefly through the celebrated Dōjigiri Yasutsuna. Older accounts treat Yasuie as Yasutsuna's pupil or as a member of the same Hōki workshop, though the exact tie is reconstructed from style rather than documents and is best read as a likely relationship, not a proven one. He is thought to have worked in the late Heian period, around the Heiji era of about 1159 to 1160, when sword production in the Chūgoku region of western Honshū, rich in the iron sands of its mountains, was already well established.

The clue that links him to Yasutsuna is the signature itself. The two characters resemble Yasutsuna's not only in their calligraphic hand but in exactly where on the tang they were cut. A workshop that passed down even the placement of a signature was passing down a complete craft, and the Yasuie blade is a quiet piece of evidence for how faithfully technique moved from master to follower in these early forges.

One twist complicates the neat lineage. Hōki blades are usually described by a darkish ground steel and a mottled surface figure called jifu. This sword shows those traits, yet its slender shape, the fine wood-grain pattern of its jigane, and the small irregular outline of its temper line all echo the old swords of Bizen Province to the east. The blade sits, in other words, between two regional traditions, and it hints that the early smiths of western Japan were connected to one another in ways the tidy school labels do not quite capture.

Why It Is a National Treasure

The sword was first designated an Important Cultural Property in April 1935 and raised to National Treasure status on 14 November 1953. The reasoning recorded by the Agency for Cultural Affairs is direct: works that can be securely attributed to Yasuie are exceedingly few, and among them this blade is the finest in workmanship and the soundest in condition. Quality and survival rarely run together in objects this old, and here they do.

That soundness matters more than it might sound. An eight-and-a-half-century-old blade that has never been shortened keeps its original proportions, its original tang, and the original relationship between signature and edge. Much of what specialists can say about how Yasuie worked rests on this single intact example. Lose it, or alter it, and a whole smith slips further into the dark.

What to Look For

Swords are difficult objects for a first-time viewer. The instinct is to look at the shape and move on. Slow down instead, and let your eye travel along the blade under the case lights.

Start with the temper line, the hamon, the bright wavering border between the hardened edge and the softer body. On this blade it runs as a small, restless pattern with clove-shaped peaks mixed in, and threads of brighter activity, called ashi and kinsuji, reach into it like roots. The upper half of the blade carries the strongest work, where the misty nioi deepens and fine crystalline nie gathers along the line.

Then look at the surface of the steel itself, away from the edge. The faint speckling there is the jifu that marks the Hōki tradition, overlaid on a tight, flowing grain. Finally, if the tang is visible or shown in a photograph beside the case, find the two small holes for the securing peg. One is ordinary; the second is unusually tiny. Such details are the fingerprints by which a blade is read, and on a sword this rare every one of them has been studied.

Around the Kyoto National Museum

The Kyoto National Museum stands in the Higashiyama district on the city's eastern side, an area dense with the things people travel to Kyoto to see. Sanjūsangen-dō, the long hall famous for its thousand standing figures of Kannon, is directly across the street. A short walk north leads toward Kiyomizu-dera and the sloping lanes of Higashiyama, and the museum sits within reach of the temples around the Kamo River's eastern bank.

The blade is part of the museum's permanent collection rather than a fixed display, so it appears in rotation, often in the sword galleries of the main collection or in special sword-themed exhibitions. Anyone making the trip specifically to see it should check the current exhibition schedule before going. The museum's own sword sections are a good place to understand what you are looking at, since they set early blades like this one beside later swords and let the changes in shape speak for themselves.