I just want to see if I can continue from the comments in the previous post, where we’re talking (clearly!) about tenouchi. I clipped out example photos from the two recommended videos. The one on the left is from the student taikai and the one on the right is from the yawatashi at a taikai in Sagamihara:
If I understand correctly, two things to notice here are the left arm, which is bent in the image on the left but straight in the image on the right, and more subtle, the orientation of the first metacarpal (the bone in the palm that connects to the thumb). The differences in the arm could be intrinsic… I’ve noticed a lot of very different bone structures at the dojo, especially among the women, and in Minna no Kyudo there is actually a diagram (pg. 115) of this form, along with a recommendation that people with a structure called saru-ude re-arrange their left hand to create the form seen here. According to the author, people who can do this tend to hit the target quite reliably, which seems to be the case. The fact that this is not her natural bone structure seems to be revealed by the way her arm changes shape in zanshin. So first, she may creating the bent configuration seen in the photo on purpose, and second, she may not have much choice.
The second point about the metacarpal is more subtle and you have to look a bit more closely even though I tried to enhance the images. What you see on the left is pretty common, where the head of the metacarpal and base of the proximal phalange form an upward-pointing triangle that the arrow rests on. The discussion in Minna no Kyudo actually mentions that people with her arm structure tend to use an upward-biased (ue-oshi-gimi) tenouchi. In contrast, in the photograph on the right, the kyudoka there (I regret that the video is not clear enough for me to make out her name) has flattened this triangle out to some extent, bringing the head of the metacarpal more into line with the wrist, arm, and force vector aligned with them.
I’m very impressed that anyone would notice this, let alone know which YouTube videos demonstrated it. When I go to practice on Tuesday I’m going to experiment myself, and also take much closer look at what people are doing. Lately I’ve been fascinated by just how much difference small changes can make. Many thanks for pointing this out.