How Is a Katana Made?

One of the most iconic national symbols of Japan is the samurai sword. The samurai sword, also called the katana, is said to hold the soul of the samurai. It has been known for its unmatched engineering and flawless beauty for more than a thousand years.

The process of making a katana requires a sound knowledge of chemical metallurgy. The traditional method involves many steps, and craftsmen work tirelessly on the metal for months, even years, to create a single blade.

The first step in making a katana is making the steel

The starting steel, known as tamahagane, is created by smelting sand containing iron ore (iron sand) with charcoal in a large clay furnace called a tatara. Once the right temperature is reached, the swordsmith must watch over the tatara, feeding in charcoal and iron sand as needed. This is an important stage and, as such, the team of smiths must be on hand for at least 72 hours.

The next step is for the team to sort the steel

Once the three-day smelt is complete, the team of smiths breaks open the clay furnace to reach the tamahagane. The mass of steel is then separated according to its carbon content. When low-carbon and high-carbon steel are skilfully combined, the blade has the right level of toughness and a razor-sharp edge. If a traditional katana were made from only one type of steel, the resulting blade would either dull easily or be too brittle.

The third step is to purify the steel

Once the second step is complete, the best pieces of tamahagane are sent to an expert smith, who heats, hammers and folds the steel repeatedly, sometimes up to 16 times, to blend the carbon and iron. This also removes impurities, known as slag.

The fourth step is to forge the blade

Once the smith has hammered out all the impurities, the high-carbon steel is heated and then beaten into a long piece with a channel down the middle. The low-carbon steel is heated separately, then hammered into a bar that fits this channel exactly. The two metals are then forge-welded together. The hard steel forms the outer shell of the katana, providing the cutting edge, while the low-carbon steel is its durable core.

The fifth step is to coat the blade

Once the katana has been shaped, it must undergo a final firing. To do this, a thick mixture of charcoal and clay is applied to the blunt back edge and the upper sides of the blade, leaving the primary cutting edge only lightly coated. This protects the blade while giving it its characteristic wavy pattern, known as the hamon. In general, the blade is heated to about 800 degrees.

The sixth step curves the katana

To achieve the signature curve, the katana is taken from the heat source and then plunged into water. The curve appears because the different steels contract at different rates and to different degrees. Once this is done, the katana is polished and mounted in its handle.

Conclusion

The Japanese sword has a long history, but it is above all associated with the samurai. Katanas have been carried by Japan's famous samurai for hundreds of years. We hope this article has shown you how this remarkable sword is made.