Kyudo Notebook: Arrow Lore

This past weekend I was in Tokyo for work, and a friend wanted to check out Hasegawa Kyuguten, a shop I’d never been to, and which is known for take-ya, so off we went. The idea was to drop in before moving on to another destination, but we were caught in a tsunami of arrow knowledge, and didn’t get out until late in the afternoon. In particular we learned about various ways that bow strength, arrow length, arrow weight, (bamboo) arrow wear over time combine with arrow stiffness, feather stiffness, type, and size… all the factors that need to be properly balanced to get things just right. Well, at least the equipment. The shooting (in particular the draw and, of course, hanare) are up to us.

But how to record all that? On the one hand maybe I don’t have to because there is a book, 「矢の知識」. If you click on the link (it’s to an Amazon page) you’ll see it’s not available online, but they had it at the shop. This is one of those books that has a sort of legendary status… I’d seen photocopies taken from it, but until now, never the book itself. Once it gets here (it’s big, so I mailed it) I hope to dive into it more. About 2/3 of it is photographs of birds and feathers.

One important point that I do remember from the marathon session is that, in the traditional view, what happens at the moment of release is that, essentially, the barbs of the fletchings “lie down” due to both their inherent flexibility and air resistance as the arrow shaft accelerates forward. Then at some point in the brief interval between the sha-i and the target, they rise back up. As you’d expect, while the barbs are lying down flat, they don’t contribute much to the stability of the arrow’s flight. It’s only as they stand up that they interact with the air stream and cause the arrow to spin around its long axis. However there’s a cost… when the barbs stand up, the increased air resistance causes the arrow to slow down.

This is where the stiffness of the feathers comes in. If you want the barbs to stand up quickly (or maybe not even lie down very much to begin with), you use feather that is stiff and perhaps a bit large. In this configuration the arrow’s construction will compensate for small errors in the shooting, such as a less-than-smooth hanare, so this is commonly what people in-the-know will use during taikai, shinsa, etc, when they want an extra margin of safety/stability. And indeed, it seems like most arrows are made like this. Certainly the turkey feathers used on aluminum arrows are quite stiff.

On the other hand, if a person wants the arrow to fly fast, and to be extra sensitive to errors in shooting (in order to make them visible, so you can learn to overcome them), they might choose feathers that are soft (so they remain lying down longer), and narrow. This explains, for example, why the fletchings on enteki-ya typically are made from soft feathers, and they’re much more narrow than in regular kinteki-ya. You can think of it as the difference between a passenger car and a highly responsive racing car. The first is comfortable, flexible, forgiving. The second does exactly what the driver tells it to do (for better or worse).

One recommended strategy was to start with relatively stiff feathers, then once you reach a kind of stability, switch to softer/narrower ones so that shooting errors will become more apparent. Then after you regain stability with those, you could try something even softer. And so on. I’m not sure how many people really do that, though. It’s psychologically difficult to give up stability once you’ve found it.

There was also something about the shafts and the shape. The most common these days are essentially straight, but at various times there have been variations: tapered so that the arrow is narrow at the front, thicker at the back (by the hazu), tapered the other way, or even tapered at both ends (chukurin). This, too, has an effect on flight and stability, as well as the center of gravity of the arrow. Also it was recommended that take-ya be taken in for a “tune up” every six months or so, especially at the beginning, to make sure they don’t warp, and to compensate for the wear at the forward end of the arrow caused by repeated abrasion as the arrow penetrates the azuchi.

Next time I go there I’ll try to record more of what was said.

There were some things that I’m still not sure about. For example, because my arrows are long, they also have to be heavy (or they’ll bend too much), and as a result I was told I really needed to be using a bow with a draw weight of 20kg or more. But my arrows fly just fine as it is, and my teacher sees no reason for me to jump to a stronger bow, so maybe this is just a case where a “rule of thumb” is only that, and there has to be some adjustment, plus or minus, for individual differences? Tempting to order another bow though…

This entry was posted in equipment, kyudo, kyudo notebook, Uncategorized. Bookmark the permalink.

6 Responses to Kyudo Notebook: Arrow Lore

  1. Zacky Chan says:

    Great info! I’m always intrigued and intimidated at how such small details can affect our shooting. How much does the gear really affect our shooting? There is a great need for this knowledge and the masters who use it to make the tools. Thank you very much for sharing. And I recommend … just ordering another bow. Haha.

  2. zen says:

    I have seen that book at the Dojo. I was told I could order it through the school. Since it was sort of costly and I do not read Japanese, I held off…for now🙂

  3. karamatsu says:

    These things are always tempting because they go out of print, but that said, if you have access to a copy at the dojo, I imagine it’s enough! I like the pictures of the birds and the feathers. Details about the shafts, etc, actually seem kind of thin, and it might be better to talk to an arrow maker. If I go to Tokyo again I may go visit… take the arrows I have and see what they suggest. I figure the only way to really know what difference these changes make is to experiment, but there is that matter of budget.
    Interestingly the latest issue of the Kyudo magazine also has an article (pp. 32-33) about arrows. Maybe the topic is “in the air” right now?

  4. F says:

    Interesting write, thank you for taking the time. To complicate things even further, the proportions are not kept with bigger arrows. I need them in 108-110 cm lenght, and the feathers are exactly the same in size as those used on a normal Japanese person’s 85-90 cm arrow. This means I’m shooting what basicaly amounts to an enteki-ya constantly😉.

    • karamatsu says:

      Same here about the shaft length, and I never thought of that… that the feathers might need to scale up. There are some ANKF regulations about the length and size of the fletchings — there’s a range allowed — but I don’t have the rule book here. Maybe I’ll check at the dojo tomorrow. On the other hand maybe the (relatively) smaller fletchings demand that we shoot better, which is a good thing!

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