Learning from Japanese Archery Technique?

Paul,

That technique is a common practice in Kyudo, it?s the right way to correctly release using a yumi. It works because the design of the yumi with its iriki shape (string to the right of limb center).
In my opinion, it isn?t advisable to use it with a short bow. You have to be carefull not to push too much to the side or the bow would be unbalanced after time.

Paul, this is an excellent post. I have been seeing this effect shooting the short bows as well, never mind the potential damage. The torque applied to the bow, similar to the Japanese technique, helps the arrows to clear the bow grip in all kinds of bows, when shot with the thumbring. I actually believe this technique allows to shoot weak spined arrows out of strong bows with no danger of arrows striking the grip. The degree of torque applied to the grip should depend on the length of draw and the physical stature of the archer.

I am not too sure if this actually makes the power stroke longer,as it is calimed in this video, but this may have to be tested by filming the short bows as well.

Adam

Looking closely at the video, I don't think that it bears out some of the claims being made by its makers. Some of the assumptions appear to be based on angles of view that distort the closeness of the arrow to the string (from behind the archer), while others show a precise view that is a little over-enthusiastically interpreted ( from the side). The arrow usually leaves the string when the string has started to slow down as it interacts with the bow limbs. A too tight nock can absorb some of the arrow's energy and cause it to lose velocity and deflect one way or the other. Sometimes we are a little too interested in the nock gripping the string and forget that it has to be able to let go easily.

The majority of the turning of the bow takes place after the arrow has left as can be seen in some sections of the video and is clear in some other videos I have seen. The real effect comes from the twisting force on the handle of the bow (torsion). This does what Adam has said with weaker spined arrows. I have noticed using a siper that the arrows seem to go straighter. The fist is turned to the left, but the strength of the bow pulls it around somewhat by straightening the wrist. I wonder if that has the same effect as introducing torsion in the bow grasp.

I used to play with a Korean bow and make it do the full rotation and have the string hit the back of my wrist. (This was a modern bow with no string offset.) My kyudoka friend told me that manually inducing the rotation in that way was not correct for a Japanese bow. However, there are Chinese paintings showing a half rotation in the horizontal plane coupled with a 90 degree rotation in the vertical plane (khatrah in Arabic) so the technique was used historically with short bows.

What is important to note in this and other similar ones is that the arrow movement you can see with these high speed pictures is often not apparent to the archer at all because it happens so fast. We are good at picking out movements which happen at some distance from the bow, but these close up ones happen so fast. As a result, you cannot directly compare your experience to one of these high speed videos.

There are some points about shooting Japanese style which might affect the usefulness of this type of video. While using the Japanese shooting glove, yugake, is a thumb release, it does not have the same effect as a thumb ring or leather thumb tab because the deflection is much greater. Secondly, the bowstring on a Japanese bow is offset from the centre line of the bow and the limbs are different lengths. This makes a difference in the way that the string moves. The two things together make the Japanese bow and its performance unique.

I don't mean that the video isn't useful, but we should be careful of making exact comparisons. You can learn a lot about archery watching the Japanese style.

I must amend my comments. I have looked at my other Japanese video again and found that they were using bamboo arrows that had a much greater flex in shooting.

I then went back to the youtube video and noticed that the shooting machine had a considerably different performance than the archer. This seems to me to be another useful piece of information you can get from the video. The performance of the arrow and the bow seemed more exaggerated with the shooting machine. Shooting machines are much harder to build than it might seem.

Did anyone notice any vertical movement on the part of the bow hand? I couldn't see any. I would not expect it, but I have been wondering if there is a vertical component when the horizontal one is minimised.

The comment of the speaker about the bowstring hitting the ear without tsunomi is untrue. All archers drawing behind the ear would have the same problem, but they don't unless they lean into the path of the string. I have shot a Japanese bow with and without the tsunomi and in neither case did I hit my ear. I have also shot Chinese bows in the same fashion. I have known of Japanese archers hitting their ear or their glasses, but usually their teachers have pointed out a problem with posture rather than their grip. The string would have to have a lot more movement to the side than it does to curve around the head. Even the computer graphic does not show a string path that would hit the ear.

Regarding the extra inch of string contact, consider this. If the bow is turning then the angle of view has changed. At all times the string is moving towards the belly of the bow. Under these conditions, the contact of the arrow with the string is extended while the string is moving at an angle to the path of the arrow. Would this not induce another vector into the motion of the arrow? Also part of the extended contact could be an optical illusion created by the fact that the bow has turned in relation to the position of the camera. I think you would need two synchronised cameras to calculate this.

I think the the technique actually does allow the arrow to stay with the string a bit longer. It is a dynamic technique and the arrow velocity may increase slightly thanks to this effect. It is hard to say though what the extra 90deg vector does to the arrow, but it certainly eliminates the contact with the grip, so dreaded by many thumbring archers.

For computer experts: is there a way to download the video? I have planned to do similar tests for a while now and would like to keep it as a reference.

Adam

Bede wrote:

Regarding the extra inch of string contact, consider this. If the bow is turning then the angle of view has changed. At all times the string is moving towards the belly of the bow. Under these conditions, the contact of the arrow with the string is extended while the string is moving at an angle to the path of the arrow. Would this not induce another vector into the motion of the arrow? Also part of the extended contact could be an optical illusion created by the fact that the bow has turned in relation to the position of the camera. I think you would need two synchronised cameras to calculate this.

A 30" arrow needs to be rotated (axis of rotation through the point) by about 15 degrees towards the observer to make it appear as 29" long, so I guess this is a possible source of error. You'd have to position a camera to monitor the arrow from above or below as this view allows for monitoring both forward and sideward motion.
Also, extended string contact does not necessarily lead to extended acceleration.

Daniel,
The average Japanese arrow is between 34 and 36 inches long so I think you might be right.

Regarding the string contact with the arrow: it only imparts extra velocity if the string is still accelerating. Simple contact because the string and arrow have attained the same velocity makes no difference. With some bows, the string stops accelerating before it reaches brace height. What you need is a string that keeps accelerating up to brace height like a composite bow.

Mr Adam - you can download this video in FLV format. I upload to rapidshare: http://rapidshare.com/files/250669289/video.flv.html

Regards
Jakub :)

Hi,

this is the technique of HEKI-INSAI-HA.
please read my explanation in: http://atarn.net/phpBB2/viewtopic.php?t=704
and see on the pictures in http://atarn.net/phpBB2/viewtopic.php?t=1302 how the thumb from the bowhand straightens until YAGORO.

Peter

Thanks Jakub, it worked very well (dziekuje bardzo za pomoc).

Adam

Pan Adam niezapomnial ? Dobrze viedziet ze mozna i po nasemu :wink:

Dusan - i Ty też jesteś Polakiem? Fajnie wiedzieć :-) Hi hi, my tu gadu gadu in polish language a reszta forumowicz?w nic nie rozumie :lol:

Why on this forum can not give "posts term of validity"?

Nie , ja jestem Slovak, ale to przeciez nie jest duza razlika nie ?Jastezme jednego rodu. :lol:

Nie wiedziałem że tak łatwo Słowaka zrozumieć, kiedyś rozmawiałem z Czechem to było trudno się dogadać bez angielskiego :) No fakt jesteśmy Słowianami :)

Jezeli mas usi otvarte a troche pogadas, to niemas problemu ani s Serbami, Chorvatami ci Ukrajincami.Naved s Bulgarami.
Sorry for litlle Slavic language . We talking about, how easy understand Slavic people each other from various contries. Same source :wink:

What is tv that have showed (bloody english verbs) this good movie?