The Japanese katana, thanks to Hollywood and assorted works of history, fiction, and historic fiction, is probably the world’s most recognizable sword. It is also one surrounded by many a myth. The katana is a single-edged curved sword, with a long handle for two-handed use. It features a square or circular guard, and a slender blade of around two and a half feet in length. Katanas are among the finest cutting weapons in history, and were used by Japanese samurai since feudal times. Their earliest recorded mention in the historic record dates to the twelfth century.
Katanas are the product of natural evolution. They started off as hefty “great swords” that grew thinner, lighter, and more agile over time in order to meet the demands of emergent combat styles that relied upon speed. They became popular with samurai because the ease and swiftness with which they could be drawn was a decided asset for the newer and faster techniques. The new combat styles were collectively dubbed kenjutsu, the art of sword fighting. The issue was often settled within seconds, and reaction time spelled the difference between life and death.
Katanas inspired many legends. They were reportedly forged by master sword smiths who hammered and folded the blade over a thousand times. They were also rumored to be so sharp that they cut through machine guns in WWII. Unfortunately, that is a pure myth. In real life, back in their heyday, katanas, coupled with a smaller sword, were thrust, sharp edge facing upwards, through the bearer’s obi – a sash wrapped tightly around the samurai’s waist. The configuration was known as daisho, and it identified the wearer as a samurai – the only people authorized to tote paired swords.
Katanas worn in the daisho style facilitated a speedy draw, ideally allowing samurai to draw and cut down opponents in a single fluid motion. An entire martial art, Iaido, was dedicated to the speedy retrieval of katanas from their scabbards. Katanas are made from tamahagane steel. It is produced by traditional Japanese smelting processes that result in layered steels with varied carbon concentrations that are welded, folded, and hammered out to reduce impurities. A katana needs a sharp and hard edge. However, steel that is hard enough for a sharp edge is brittle, while softer steel that is not brittle will not take and retain a sharp edge. That posed a problem for sword smiths.
1. The Folding of Katana Blades Thousands of Times is a Myth
Katana makers solved the dilemma of a sword that had to be both sharp and hard-edged via the use of four metal bars. A soft iron bar to guard against breakage, sandwiched by two hard iron bars to prevent bending, and rounded off with a steel bar to take the cutting edge. The result was a sword that had a hard enough blade, and a sharp cutting edge. However, contra many a WWII tall tale, no katana was ever hard enough, or sharp enough, to cut through machine gun barrels. The four metal bars of which katanas were made were heated at high temperatures, then hammered into a long bar that would become the blade.
Contrary to myth, katana blades were not folded thousands of times. So many folds would be counterproductive, and render the steel useless for a sword. Instead, katana blades were folded between eight to sixteen times. When the sword was sharpened, the steel took a razor-sharp edge, while the softer iron kept the blade from breaking. Well-crafted katanas became prized heirlooms, passed down generations of samurai families for centuries. Magnificent specimens of centuries-old katanas can be seen in the Tokugawa Art Museum in Nagoya, Japan.
Where Did We Find This Stuff? Some Sources and Further Reading