Nihonto--The Japanese Sword

Nihonto

The word Nihonto is a comprehensive term used to describe the entire subject of Japanese swords. This includes types, etymology, construction, history, and so forth. Historically, Japanese smiths have consistently produced the finest blades in the world, and antique swords are a much-prized and sought-after item in blade shows and auctions.

The thing about Nihonto that most impresses collectors, experts, martial artists, and simple admirers alike is their incredible strength, durability, and edge-holding ability. The secret behind a Nihonto's strength is the Japanese smiths' method of forging the blade. Steels of different properties are laminated together, each steel's strength canceling out another type's weakness as its own are canceled by the qualities of the others. Numerous new lamination techniques have been introduced over the years but, as is often the case with a very refined art form, the methods still in practice from centuries earlier have usually proved to be the best. A Nihonto's value is partly determined by the complexity of the lamination used in its construction. The combination of the laminated steels and the heat-tempering of the blade to give it a hard edge (hamon) renders the finest Nihonto virtually unbreakable.

The lowest-grade blades are of the Maru kitae, or unlaminated, variety, composed entirely of Hagane (hard steel). While this might strike the novice as an advantage, in reality it is a lethal shortcoming: Hagane is brittle. The blade would be able to be sharpened almost limitless times but it would also likely develop severe stress cracks, even break outright, as it saw use in combat. This was a problem that often plagued the lower-ranking samurai, as they could not afford weapons of higher quality than Maru-kitae.

The Kobuse, Makuri, Wariha Tetsu, and Gornai kitae are all two-metal lamination techniques. Kobuse kitae was the technique used on most WWII-era nihonto; it involves laminating a thick layer of Hagane in a point-tipped "U" over a core of Shingane (soft, "core" steel), so that the mune (back) is softer and more flexible. The Makuri kitae is similar to this, but the Shingane takes on exactly the same shape as the whole bladeÐ'--unlike the core of the Kobuse, it is not round. Also, the Hagane completely surrounds the core on a Makuri kitae blade. While not as flexible as Kobuse kitae, they are much less likely to break than Maru. Wariha Tetsu kitae is an uncommon lamination method, in which no Shingane is incorporated. Instead, a kite-shaped edge of Hagane is set into a solid zukuri body of Kawagane ("skin" or surface steel). The Gornai kitae technique is an adaptation of the Kobuse kitae in which a reinforcing second core, this one of Hagane, is contained within the Shigane.

The strongest lamination types include the Honsanmai (or simply "sanmai"), Shihozume, Orikaeshi Sanmai, and Soshu kitae. Honsanmai is the technique most commonly seen in forged Nihonto. It is composed of all three steel strengths: the ha of Hagane; the shinogi-ji (blade flat) composed of Kawagane; and the core, exposed at the mune, is of Shingane. Shihozume kitae blades take this one step further, with a rectangular cross-section core of Shingane and a mune cap of Hagane. The Orikaeshi Sanmai kitae is almost identical to the Honsanmai, except for the fact that the blade is forged together vertically of two halves. The strongest lamination technique, the one used by the legendaryÐ'--indeed, immortal, if there is such a thingÐ'--sword smith Masamune, is Soshu kitae. This is a seven-layer construction method incorporating all three strengths of steel, with the mune, outer skin, and ha of Hagane, a side layer under the skin of Kawagane, and a core of Shingane.

The Japanese blade has evolved through six distinct periods: The Chokuto, "Ancient Sword;" the Koto, or "Old Sword:" Shinto, "New Sword;" Shinshinto, "New New Sword;" Gendai/Kindai, and the Shinsaku, or Modern era. These eras correspond more or less with the eras of Japanese history sometimes containing or joining two of the historical eras within their bounds.

Very, very few swords survive from the Chokuto period, which comprised Nihonto history up until A.D. 900. The few Chokuto swords that do survive were forged chiefly by smiths from China or Korea, and occasionally by the early Japanese smiths. The tempering in these swords is faulty, and they are little more than deteriorated imitations of Chinese blades.

The Koto era, covering all Nihonto forged 900 until 1596, actually produced many of the finest, and the most technically advanced, blades the world has ever seen. Masamune, possibly the most revered smith in Japanese history, hailed from the Kamakura period of the Koto Era. His blades, in the more than five hundred years since his life, and those of his most brilliant contemporaries in the school in Sagami province,