Forging is a common metaphor when talking about training, whether it is in the martial arts, the military, or anywhere else that people learn to handle stressful encounters. This is true in Japan and the West. We speak of forging character. In English, when we speak of forging it refers to shaping something. When we forge a knife, we are hammering it into the proper shape. “Forging character” implies developing personal character in a situation of stress and pressure.
When the Japanese talk about forging,tanren 鍛錬, they have a somewhat more complicated image non-Japanese do. It’s not just the idea of beating hot metal into shape, and hardening the steel. There is a critical step before this in the process of forging a sword. You have to hammer and fold the steel many times before the steel is ready to be shaped. This process usually takes as long or longer than the process of shaping the blade.
The idea is that the Japanese go through this repeated folding and hammering of the steel to create a multitude of layers in the steel. These layers of hard and soft steel make a blade that is both able to endure severe impacts and hold a sharp edge. Steel that is homogenous will either be soft or hard. Soft steel will absorb impact without cracking or breaking, but it bends easily and a sharpened edge will dull quickly. Hard steel will hold an edge well and resist bending, but it is brittle and liable to crack if struck hard. The ancient Japanese technique of layers of hard and soft steel makes for a blade that has hard layers that will hold an edge and soft layers that will absorb impact.
This great blending of the properties of hard and soft steel was not the reason Japanese smiths started repeatedly hammering and folding their steel though. They were driven by something else that colors the Japanese concept of forging. The steel used to make Japanese swords is probably the lowest quality, most impure and contaminated stuff to pass for steel in the world. It’s called tamahagane. It’s made by collecting iron bearing sand which is then melted in a crude earthen smelter by adding charcoal directly to the material being smelted. As in any smelting process, most of the impurities and stuff that isn’t iron melts and runs off. The classical Japanese smelter isn’t very efficient or effective though, so a lot of impurities remain in the resulting steel, as well as an abundance of unburned charcoal bits. No self-respecting smith would touch this stuff.
In Japan it was all they had, so they figured out how to make it work. Their solution is slow and takes an incredible amount of effort, but the outcome not only transforms the steel into high quality material, but creates all those layers that make for a stronger, sharper blade with the incredible patterns in the steel that contribute to making Japanese swords the most beautiful in the world. The patterns on the surface are subtle and complex, giving a picture of the complexity and beauty of the internal structure of the swords.
How does heating and folding the steel get rid of all the impurities and chunks of charcoal to leave the beautiful, layered steel with a grain like wood? The smith heats the billet and hammers it out so it is long enough to be folded in half. Every time the smith strikes the metal, glowing bits are smashed off of the billet and go flying into the air. Those glowing bits aren’t steel. They are impurities, slage that would removed in more effective modern smelter. As the smith repeatedly hammers, folds and hammers the steel, more and more of the impurities are driven out of the steel. Occasionally splinters of unburnt charcoal rise to the surface as well. These pieces have to be raised up with the tip of a file and pulled out with tongs. After 10 to 20 repetitions of hammering the billet out to the proper thinness and then folding it in half, the steel is pure and the layers have been welded together by the force of the hammer. Sometimes you will only have half as much material as what was there before you started heating and hammering.
All of this has to happen before you can begin to shape the blade. This image of forging, where you have to heat and hammer the metal to purify before you begin shaping it into a blade is an important one when you think about training in Japanese martial arts. The image of tanren is one whereby the student has to be purified and have all the slag and residual garbage driven out of her before she can begin to be shaped into a martial artist is an important difference. The western image is that we take students and they are ready for forging. The Japanese image is one where the student has to be prepared before they can even begin to take the shape of a martial artist.
This explains a lot about some of the traditional stories of teachers having students do seemingly ridiculous things for weeks or months before they begin teaching them martial arts. These stories are about how teachers prepared their students to learn the art, in the same way that a smith prepares a block of steel to be able to take the shape of a sword. Students rarely come into the dojo perfectly ready to learn. I know I wasn’t ready to learn in anything approaching an optimal manner when I started, and I have seen very few students who were. This image of tanren gives us another, and more accurate, view of the role of the teacher.
We don’t just teach students our arts. New students come in eager to learn budo, but most of them really aren’t ready to start learning. I know I wasn’t. Most people who come into the dojo don’t know how to stand or even how to breathe (unless they were lucky enough to play a wind instrument or sing in choir). Before a student can begin learning budo, they have to learn to do things that are fundamental to all of life, but which don’t seem to be considered worthy of teaching anymore. We have to teach them how to breath and how to stand and how to walk.
I’m one of the lucky ones. I played trombone for 10 years before I started judo, so I had the breathing part down solid. I only had to learn how to stand and walk. I worked on good posture and basic walking for months before I really got it. Learning to counteract 20 years of bad habits acquired while slumped on the couch in front of the TV, or slouching over the desk while pretending to do your homework takes time. These kind of habits are buried deep, so learning to break them takes work.
This is where the idea of 鍛錬 tanren starts to make sense. We all have habits and traits, both physical and mental, that get in the way of learning good budo. We really can’t start learning budo until we get rid of these counterproductive habits and traits. You don’t put the foundation for a building on on sand. You don’t form a sword from ore that is still loaded with slag. You can’t really learn budo until you get rid of the counterproductive habits and traits you’re carrying. You can’t learn budo if you’ve got a bad slouch or you can’t breathe fully and efficiently. The teacher’s job is to hammer and forge you to help you get rid of these traits so you can start learning. Once you learn how stand up and breathe, then you can start learning budo. This preparation, that’s part of the forging process. That's tanren.