Samurai Gaiden: Japanese Swordmaking (Audience Request!)

We’re doing all kinds of new things with the new channel. New opening and ending animations, better outros, and now we’ve got a new thing: Question from the audience. Javacentral asks us the tried and true samurai history question: “How do they make katana?”

So today we’re going to do a neat little thing and use this video to explain the process, in simplified terms, of Japanese sword-making.

Now as a caveat, we’re going to talk about traditional manufacturing. If you’ve ever seen modern sword-making it is not very interesting. A bunch of sweaty Chinese men pull hot pieces of rebar out of a foundry and run it under an auto-hammer until they’re flat.

So the first thing we need to discuss is Tamahagane. Tamahagane literally translates as “Round Steel”, but figuratively it means gem-like steel. A common misconception is that Japanese steel is of exceedingly high quality, but in reality Japanese steel is very low quality. Unlike most European swords which were made by producing pig iron and then refining it and creating steel through that process Japanese steel is made from very low-quality magnetite iron sands, called satetsu.


The satetsu is traditionally placed into a clay tub, called a tatara, and then mixed with a source of carbon, traditionally charcoal. However I have seen in modern times even traditional swordmakers using a large metallic foundry wherein the iron sands and charcoal are dumped into the top and the resulting tamahagane is pulled out from the bottom.

So the myth is that katana are so strong because they’re two, or even sometimes three, different types of steel folded multiple times over to create a steel-layered weapon. The truth is that Tamahagane is actually still a fairly low-quality steel. That is why the folding of multiples types of steel is done. Not because it makes Japanese swords the greatest steel, but because without it Japanese swords would be complete junk.

Traditional-style tatara furnace.

Before the age of katana the Japanese made swords more in line with the old Chinese style, the Tsurugi being the basic type of Japanese sword during the pre-Heian periods. Even in Heian periods the de facto samurai piece was the Tachi, a sword designed for use from horseback. The katana derives from this Tachi style, but it is still different in ways. Length, the way it is worn, the way it is used, etc.

It was during the Heian period that the katana first started to really become popular and then by the Muromachi period they were the standard side-arm of the samurai.

But back to how they’re made. You see the swordsmith takes the Tamahagane and separates it into two, or as I said sometimes three, distinct types. These types would be Hagane – hard steel, Shigane – soft steel, and the third type is Kawagane – medium steel.

So the lowest and cheapest swords would just have Hagane steel, folded a few times, and forged into a sword. This would be a junk blade for a peasant person or for a simple knife. Or more modern wall-hanger swords are said to be done in this style – hence why you really shouldn’t use the modern rat-steel blades for cutting purposes.

The steel could be layered in numerous different ways and each smith could be different in how big of a medium piece he used, how thick of a hard layer, whether the softer Shigane was placed on the sides of the blade, and so on.

In the end what you get is a bunch of hard steel, which retains its shape and holds an edge well, wrapped around a softer core center, which allows for flexibility and durability. These types of steel are then forge-welded together creating a compromise of sorts between the multiple types of steel. The edge is not so hard and sharp as an all-hard steel blade, but it also won’t shatter the first time you swing it. Likewise it is not so durable as an all-soft steel blade, but you’ll actually be able to use it to cut something.

So, now that we’ve got that out of the way…let’s go onto the next step. After the various pieces of Tamahagane are forged together the smith would then coat the blade in clay mud. He would use different thicknesses and mixtures of mud before performing the quenching process.

Clay on blade.

This is a big part of why the katana is shaped as it is. The back of the blade has a different clay on it than the front, causing the molecules of steel to react differently on the front of the blade than to the back. The clay-coated quenching process also creates the wavy line on the blade, called the Hamon.

Hamon – wave pattern on blade.

Once the forging and quenching is complete the blade would then be signed, by chiseling the smith’s signature into the tang of the blade.

With the tang signed, the blade is then polished using whetstones of varying degrees of coarseness. Eventually you wind up with the beautiful, brightly shimmering, katana.

So, like I said, this was a question submitted to us by Javacentral. If you want to see what they’re up to, they’ve got an interesting video on coffee in Japan which we have the link to. Check them out and don’t forget to subscribe for more Samurai Gaiden.


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