Physical consideration of KYUDO -Japanese archery

Physical consideration of KYUDO -Japanese archery  8. About uniting the Expansions of the Body (伸び会い/Nobiai) <Uniting the Expansions of the Body (伸び会い/Nobiai)> This is particularly abstract and difficult to understand. However, it is essential for achieving consistent accuracy and a sharp release. The full draw (会/Kai) state appears static externally, with no extension of the arrow length or body, yet the phrase expansion (伸び合い/Nobi-ai) is used. This is a different expression from tension (張り合い/Hari-ai), so it's certainly something different from tension. I interpret the expansion (伸び合い/Nobi-ai) as a way for a person to generate the explosive power needed to perform the next action instantly. Some explain it as being for generating arrow speed, but from a physical standpoint, it's unlikely to affect the initial velocity of the arrow, and I believe it's an illusion caused by hearing or sight. To put expansion (伸び合い/Nobi-ai) simply, it's the state of preparation for...

Physical consideration of KYUDO -Japanese archery 7-4. About Tension (張り合い/Hariai)~How to release a grip (取り懸け/Torikake) naturaly~ <Tension (張り合い/Hariai)>Continued Should the thumb of the right hand be bent towards the nail? The joint at the base of the thumb (the third joint) is located near the wrist. When the bow's force is applied to the base of the left thumb, if the bow and the left hand do not form a cross shape, this third joint will bend under the force of the bow, resulting in a flat (べたおし/Beta-oshi), uncontrolled push. Since you cannot control the bow's position with a flat grip, wrap the leather around the base of your thumb, from the joint at the base of your thumb to the tip, and bend your thumb so that your thumbnail points upwards, so that you can press the bow straight down. Some people say that it's fine as long as the center of your palm forms a cross shape, but the force from the bones creates a downward rotation moment, causing the bow to tilt for...

  Physical consideration of KYUDO -Japanese archery 7-3. About Tension (張り合い/Hariai)~How to release a grip (取り懸け/Torikake) naturaly~ <Tension (張り合い/Hariai)>Continued So, how can we release our grip? How can we solve this while crossing our thumb and middle finger? This is similar to solving a difficult puzzle. You mustn't let it explode, but the release must be light and steady. These are completely contradictory. So, I think it's understandable that many people grip the strings tightly to prevent accidental release, and then open their hand to release. Here's what you can do to create a natural release that disengages the bowstring: (1) When gripping the string (取り懸け/Torikake), apply a slight twist (弦捻り/Tsuru-hineri) to it. (2) When raising the bow and arrow (打起し/Uchiokoshi), continue twisting the string. (This opens the bow and arrow and prevents the arrow from falling out.) (3) Even when the bow is half-drawn (大三/Daisan), continue to apply the twist to the string. ...

Physical consideration of KYUDO -Japanese archery 7-2. About Tension (張り合い/Hariai)~How to release a grip (取り懸け/Torikake) naturaly~ <Tension (張り合い/Hariai)>Continued Now, the balance of forces at full draw (会/Kai) can be expressed by the following equation: Bow force = Force applied to the skeleton + Muscle strength supporting the skeleton + α (Force to extend both arms through the follow-through (残身/Zanshin)) When the draw (引き分け/Hikiwake) is over, this α is almost 0. During a full draw (会/Kai), this conversion of force is what we call tension (張り合い/Hariai). By making α as large as possible, you can produce a sharp, powerful and wide follow-through (大離れ/Oh-banare). So, what exactly should we do? As explained earlier, the force applied during the draw (引き分け/Hikiwake) is applied in the direction of folding the arm, while the force applied during the full draw (会/Kai) is converted into the direction of opening the arm. The force that guides the right hand straight through to the follo...

  Physical consideration of KYUDO -Japanese archery 7-1. About Tension (張り合い/Hariai)~How to release a grip (取り懸け/Torikake) naturaly~ <Tension (張り合い/Hariai)> To put it simply, "tension (張り合い/Hariai)" is the state of continuously applying force in the following three directions until release. If any other force is at work, the pushing hand or drawing hand will become unstable, and the arrow will not fly in line with the target. You would end up deliberately shifting the target you carefully aimed before releasing it. Tension (張り合い/Hariai)≈  The force of pushing straight along the arrow axis with the bow hand + The force of opening the draw hand straight along the arrow axis to the follow-through position + The force of releasing the grip and twisting the string, centered on the thumb It's helpful to understand the tension (張り合い/Hari-ai) of a full draw (会/Kai) as the state in which the entire body's strength, combined with the upper body's actions, creates th...

Physical consideration of KYUDO -Japanese archery 6. About uniting the Firming Points of the Body (詰め合い/Tsume-ai) From here, I would like to explain the specific method of releasing the arrow by uncrossing the fingers at the grip (取り懸け/Torikake). After reading this, you will probably be able to approach your Japanese Kyudo shooting technique in a different way than before. To achieve a natural release, it is said that in a full draw, "Uniting the Firming Points of the Body (詰め合い/Tsumeai)", "Tension (張り合い/Hariai)", and "Uniting the Expansions of the Body (伸び会い/Nobiai)" are essential. But what exactly are "Uniting the Firming Points of the Body", "Tension", and "Uniting the Expansions of the Body"? This is a question everyone has, but few people can express it concretely; instead, it is expressed in terms of sensation, philosophy, or tradition. I would like to explain it as concretely as possible so that everyone can experience ...