Angular momentum

Apologies for being so quiet lately. I thought that I’d share this little blog post examining sayabiki (the pulling back of the scabbard with the left hand to draw the Japanese katana with the right hand) from the physicist’s perspective of conservation of angular momentum:

Sayabiki and Angular Momentum

This is an interesting point, although I think that it is more relevant to, say, the dynamics of a throw in Aikidō than drawing the sword in Iaidō. While I don’t doubt that using sayabiki to exploit the conservation of angular momentum does allow a more powerful draw, I think that the primary reason for sayabiki is simple mechanics: if one does not retract the scabbard, then the sword will not come cleanly out of the scabbard mouth — if the sword comes out at all, then its cutting tip will damage the scabbard and indeed the Iaidōka’s hand!

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Using the ukemi / meditation mindset

On Monday, I underwent a surgical procedure (a bursectomy) to try to correct my long-standing knee problem (chronic prepatellar bursitis). As for the recovery, so far, so good. The key factor determining my long term recovery of function will be how well the wound closes (no little gaps or bubbles = very good).

Of course, as with any surgical intervention, there’s some post-operative pain. What strikes me very strongly is that when the pain hits, experiences like Zen meditation and taking ukemi are of great practical value: being able to relax, to acknowledge pain and discomfort without suffering and allowing them to become all-consuming, and above all to keep some semblance of good humour through it all — these things are really, really useful.

Title

The title of this blog comes from a Japanese phrase often applied to the martial arts, but also to other disciplines such as the tea ceremony.

動 — “dou”, move, happen, movement, action
中 — “chuu”, central, centre, middle, in the midst of, hit (target), attain
の — “no”, possessive suffix
静 (or 靜) — “sei”, quiet, still, motionless, gentle

Thus, 動中の静 means “the stillness of/in the midst of motion”, or “calmness in action”. It’s very difficult for me to articulate it precisely, but this seems to me to be among the cardinal qualities (virtues?) of the martial arts. The moments when I feel it in Aikido, Iaido or Zazen practice — or just in ordinary daily life — are sublime and priceless.