Sword (Unsigned Masamune (famous Kanze Masamune))

A Katana by Masamune, the Smith Whose Name Became a Word for Excellence

The blade known as the Kanze Masamune is a katana of 64.4 centimeters, attributed to the swordsmith Masamune of Sagami Province, the area covered today by part of Kanagawa Prefecture. It carries no signature, yet it is counted among the finest works of the most renowned smith in Japanese history. The Tokyo National Museum holds it, and it ranks as a National Treasure.

Masamune worked at the close of the Kamakura period, in the early fourteenth century. He was known by the name Gorō Nyūdō Masamune, and tradition records him as the son or adopted son of the smith Yukimitsu, trained under Shintōgo Kunimitsu. From that lineage he developed a forging method that became the Sōshū tradition, one of the five great regional schools of Japanese swordmaking. His reputation grew so large that in later centuries the word "Masamune" came to mean a superb sword in itself.

To understand why this particular blade carries no maker's mark, it helps to know how it reached its present form. It began as a longer tachi, a sword slung edge-down from the belt. At some point a swordsmith cut down the tang and shortened the whole weapon into a katana worn edge-up, a process called ōsuriage. Shortening this much removes the lower end of the tang, and with it any signature the smith had cut there. What survives on the tang instead are carved devices, including Sanskrit characters, that were added higher up the blade.

Why It Was Named a National Treasure

The sword first received protection as an Important Cultural Property on February 8, 1958, and was raised to National Treasure status on June 27, 1959. Its designation number in the national register is 00224.

The case for its value rests on the quality of the steel and the way the surface reads in light. Connoisseurs of Japanese swords look closely at the jigane, the grain of the forged steel, and at the nie, the scattering of tiny bright martensite crystals that gather along the temper line and across the surface. On this blade the nie is regarded as exceptional, a sparkle that catches and holds the eye when the sword is turned under light. The width of the blade runs slightly slender, which gives it a quieter, more controlled presence than the broad-bodied works of the following Nanbokuchō era.

There is one historical curiosity worth keeping in mind. Because so many works given to Masamune are unsigned, scholars in the Meiji period went so far as to doubt that such a smith had existed at all, an argument later called the Masamune denial theory. Documentary references and surviving blades have since reassured most specialists that he was a real figure of the late Kamakura-era forges, though his exact birth and death years remain unknown.

What to Look For in the Blade

The temper line, or hamon, follows a pattern called notare, a slow and gentle undulation rather than a series of sharp peaks. This was a signature effect of Masamune's workshop, achieved by controlling how the clay coating and the fire shaped the hardened edge.

Look also at the tang. Where many shortened blades lose everything when cut down, this one keeps carved Sanskrit letters and other devices that the maker placed near the base of the blade. Such carvings tie the work to the religious and artistic habits of the Sōshū smiths, who often added Buddhist imagery to their swords.

The provenance is part of what people travel to see. The blade takes its name from the Kanze family, the leading house of Noh theatre, which once owned it. According to the Edo-period sword catalogue Kyōhō Meibutsu Chō, Tokugawa Ieyasu took the sword from the Kanze family and passed it to his son Hidetada, after which it moved repeatedly between the Tokugawa house and its retainers as a gift and a token of favor. After the Meiji Restoration the Tokugawa family presented it to Prince Arisugawa-no-miya Taruhito, and it later came to the Takamatsu-no-miya household before entering the national collection. A single object that carried this much social weight tells you something about how swords functioned in old Japan, less as weapons than as objects of rank and memory.

Seeing the Sword and Exploring Ueno

The Kanze Masamune is not on permanent view. As a fragile and important object, it appears in the Japanese sword gallery of the Tokyo National Museum only at intervals, often a few years apart, and it travels occasionally to special exhibitions. Anyone hoping to see the actual blade should check the museum's current exhibition listings before visiting rather than assuming it will be on display.

When it is not out, the same gallery, Room 13 of the main building, shows a rotating selection of other fine swords, so a visit still rewards anyone drawn to the craft. The museum sits inside Ueno Park, an easy walk from Ueno Station, and the surrounding grounds hold several other major institutions, including the National Museum of Nature and Science and the National Museum of Western Art. The park is among the best places in Tokyo for cherry blossoms in early spring, which makes a sword viewing easy to fold into a longer day outdoors.