The Ancient Art of Japanese Swordsmiths

CNN recently profiled a Japanese swordsmith and the ancient, exacting process he follows to craft a katana.

The blades are forged from tamahagane, a steel whose layers contain differing amounts of carbon. Shimojima painstakingly heats, softens and then folds the steel in order to remove impurities and even out the carbon content.

​“A single layer becomes two layers, then two become four, four become eight and so on,” he explains. ​“By folding 15 times, over 32,000 layers are produced. However, it does not mean that the more layers, the better. There’s of course a limit, and if you exceed the limit you lose … the strength required to serve as a sword.“

Next, the sword is shaped — although it begins completely straight. As the steel is hardened through a process of repeated heating and cooling (known as yaki-ire), the differing densities in the blade’s structure create its signature curve.

​“In the space of 10 minutes, we heat up the blade to about 800 degrees centigrade and rapidly cool it down in water,” Shimojima says. ​“It seems like a simple process. However… it’s a matter of making a split-second judgment.”

I’ve long been fascinated by Japanese swords. They’re really quite beautiful in their aesthetics, simplicity, and utility.

Read more about Japan.