Paul Martin thinks Japanese swords are a miracle.

The soft-spoken Englishman becomes animated when he talks about nihontō, the subject to which he has devoted his professional life for the past 25 years. During a hands-on lecture held at the Samurai Museum in Shinjuku, Tokyo, he helps students to understand his passion for swords, which are both weapons and art objects. A leading expert and former curator of Japanese swords for the British Museum, Martin explains that the swordsmiths of centuries past used sublime skill to imbue their steel with subtle, beautiful patterns in ways that are still not understood today.

“This technology has been lost,” he says, pointing to an enlarged photo showing the edge pattern, called hamon, of a sword forged by Ichimonji Yoshifusa, a renowned smith of the Kamakura Period (1185-1333). Layers of frosty, whitish crystals billow along the length of the blade like clouds. Or perhaps like waves. Or then again, like the tree-line of a forest seen through mist. “Everyone sees it differently,” he says, which is part of the artistic appeal of the Japanese sword.

Specimens from this early period (794-1600) are known as kotō, “old blades.” It is not known exactly how the early smiths produced such naturalistic and uncontrived temper patterns, although more recent smiths have also achieved high levels of mastery. “There is a theory that they didn’t use clay (during the quenching process), and that this is just the pattern of the water bubbling up the side of the blade,” Martin says.

During his lecture in a quiet tatami-fitted room, he explains the forging process: Rapid cooling of the red-hot blade results in the formation of crystalline steel along its edge. In some places, this manifests as a milky pattern composed of microscopic crystals called nioi. In others, bright dots called nie form. The effect, he says, looks much like scattered stars spread out across the backdrop of the Milky Way.

Later smiths of the so-called shintō (“new swords”) period used clay during tempering and quenching, painstakingly applying it to the blade to produce naturally inspired hamon patterns. They undulated like waves, emulated the young buds of clove flowers or even mimicked the silhouettes of pine forests. Looking closer still, the metal itself reveals a fine grain pattern (hada) that is the result of repeated folding and hammering of differing kinds of steel during forging. Some hada resemble straight timber grain, while others look like wood burls or waves.

Discussion of nihontō often includes nature metaphors. As with most classical Japanese art, the natural is inextricably mixed with the man-made. Swords in particular are viewed as being a potent mix of natural elements: Iron sand is made into steel through an admixture with carbon to make steel billets. These are forged in pine charcoal fires stoked with a hand-pumped bellows, then coated in clay and quenched with water. The resulting blade is then precisely shaped and polished into a final form that, with its mathematically pure elliptical arcs, flat planes and straight edges, reflects the human intellect.

Of course, the sword was originally conceived as a deadly weapon. Over the centuries its shape evolved to adjust to changing requirements on the battlefield. Following the introduction of straight swords from China, a curve was added, boosting cutting power. As cavalry gained prominence, the sword hung suspended from the belt of mounted samurai in a way that facilitated drawing and use with one hand while the other held the reins. Further innovations resulted in the blade being worn edge-up in the sash. When the peace of the Edo Period (1603-1868) fell over Japan, straighter blades became more desirable as samurai settled down and took up kendo in the cities. All of these subtle traits enable an expert to estimate a blade’s age with a glance at its shape.

But Martin stresses that the nihontō was always more than just a weapon. In the creation myths of Japan, the storm god Susano-o slew an eight-headed dragon and discovered in its tail a magnificent sword known as the Kusanagi-no-tsurugi (“grass-cutting sword”). He gave this to his sister, the sun goddess Amaterasu, who bequeathed it to her descendants along with a jewel and a mirror — the three sacred objects that form the Imperial Regalia of Japan. Since that time, swords have been thought to be imbued with significance befitting their sacred origins. They were prayed over, inscribed with religious scripture and symbols, given names and regarded as protective talismans. Many were passed down from generation to generation as closely guarded family treasures, which is why so many blades have weathered the centuries until the present day.

Swords are not just a matter of history — their making is a form of artistry that is very much alive in the present day, and one that is all too often underappreciated.

“They don’t get the recognition they deserve as art,” Martin asserts. A sword once owned by the warlord Uesugi Kenshin (1530-1578) and designated a national treasure made news in 2016 when it was purchased by the city of Joetsu, Niigata Prefecture, for ¥320 million ($2.8 million). “When you compare that to a Rembrandt, which is 400 years younger but sells for $40 million, I think swords are undervalued,” he says. Part of the problem is that most people have no idea how to appraise and appreciate swords as art.

Martin is trying to remedy this with his lectures at the newly established Samurai Museum in Shinjuku. The facility is chock full of armor, weapons and samurai artifacts, and is a perfect starting place for learning more about the warriors of ancient Japan. Unlike a typical museum, where English information is often frustratingly scant, this is a very tourist-friendly experience. Staff at the museum said that around 90 percent of the visitors are from abroad, and tours are held regularly in both English and Japanese.

Martin’s 90-minute lectures, usually held two or three times a month, are a perfect opportunity to hear from a leading expert in an intimate, small-group setting. Whereas other museums require you to peer at swords through a layer of glass, here participants get a unique opportunity to examine them first-hand. Participants can hold the swords, get a feel for their heft and balance, and appreciate their strength and beauty — but don’t touch the polished blades directly, or talk when you’re holding a sword. “Moisture from your mouth when you speak can cause the sword to rust,” Martin cautions.

Today, modern smiths continue to make swords using the old methods. To maintain stringent quality standards, all smiths must be licensed and may produce only a limited number of pieces per month. Apprenticeship to become a smith takes five years, after which they may submit their work to pass a test and receive their license. There are around 300 smiths working in Japan today, of whom 23 are classed as mukansa — supreme masters who are “beyond examination.”

Having been forged and shaped, a sword is next sent to a polisher, who finalizes the planes along the edge and gives the blade its mirror-like finish. If anything, Martin admits, the polisher’s job is even more demanding than the smith’s. Whereas a smith produces only new swords and works in a particular style, a polisher is often called upon to restore old blades, and thus must know how swords from a many eras should look.

Next, a small army of craftspeople come together to create the furniture that surrounds the blade. Makers of habaki craft the custom-fitted collar to the base of the blade. Metalworkers engrave beautiful and elaborate tsuba hand guards. Tsuka-makers wrap braided silk over a layer of ray skin to create a slip-resistant handle. And saya-makers carve and paint the scabbards in durable urushi lacquer.

For the samurai, the sword was a protective talisman, the deeply personal tool of his trade and a mirror of his soul. Strong swordsmanship reflected a pure heart, while a corrupt spirit manifested itself in imperfect techniques. It was a symbol, too, of the unification of natural elements with human ingenuity that together created a fearsome weapon. But the sword was also the product of devoted adherence to craftsmanship pushed to its highest level, resulting in a magnificent expression of lasting artistry.

How to appreciate a Japanese blade

Sword expert Paul Martin says there are three main points to assess:

Sori (curvature): How much does the sword curve, and where? Is the curve deep, gentle or absent? Some curvature is uniform (like a portion of a large circle) but in many older blades, the curve is deepest near the hilt, making it easier to draw with one hand. Sori varies from period to period, but the curvature should be natural, “Like the drooping branches from a willow tree,” Martin says.

Hada (grain pattern): Look closely at the metal — try to catch light reflecting from its surface. Tiny striations will appear in the steel like the grain in a piece of cut wood. Is the grain tightly packed, or open? Is it straight (masame), wavy (ayasugi), or burled like knots in wood (itame)? The grain has hues and textures that can tell an expert where the sword was made.

Hamon (hardening pattern): Running along the cutting edge is the hamon, which often appears as a white, cloudy line. It may be straight (suguha), wavy (gunome), or irregular (midare) — and may contain sparkling points or small lines like bolts of lightning.

According to Marin, an excellent blade balances all three elements in harmony. It may have a fine shape and an eye-catching hamon, but if the grain is badly forged, it will never be a great blade.

Finally, the viewer should ask themselves: What is the overall impression the sword makes? How does it make you feel? Is it elegant and graceful, with a subtle hamon and tight, controlled grain? Or is it bold and powerful, with a wavy grain and a flamboyant, active hamon? In the end, as with all art, beauty lies in the eye of the beholder.

To attend Paul Martin’s Japanese Sword lectures or to find out more about the Samurai Museum, visit samuraimuseum.jp/en. Admission to the lecture and the Samurai Museum together costs ¥5,000.

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