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!

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.


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.


I’m off the mat for a while, hopefully just a couple of weeks, while I rest an injury to my right knee. I’m no stranger to knee injuries, and in fact had this particular one in my left knee 5–6 years ago; that one eventually required surgical intervention, and I’m hoping that I’ve caught this one early enough to prevent the need for such drastic measures. Even so, having to take time off to heal is not exactly fun.

Continue reading “Downtime”

Aims for Examination and Education

I’m not entirely sure of the origin of this quote, which I’ve found in several places on the web:

“The education system is so geared toward fact drilling and rote memorization that students often exit with a head full of dates and formulas, but without the ability to constructively think. Now, if we readjusted the testing and educational system to focus on critical reasoning rather than memorization, then even if we knew fewer facts off the top of our heads — we would be smarter overall. We would take a step toward doubt – and a step toward thinking for ourselves.”

I heartily agree with the sentiment; although I think that to properly learn from the mistakes of the past one needs substantial fact recall as well as critical thinking ability. I have much less problem with tests and examinations when they test this kind of skill: metaphorically, how well you can fish as opposed to how many fish you have brought with you to the exam? In practical terms, it’s very difficult to test e.g. pure reasoning skills with no assumed (memorized) facts or axioms. Nevertheless, it’s something that I’d like to see more of in all tests in all walks of life; hence, training for that exercise should be a core element of all teaching. Independent, accurate exercise of reason (and its congnates in the physical arts) is our greatest potential as human beings, and all that separates us from being mere slaves or machines.

That really opens the door to a very big discussion on free will and how deterministic the universe really is, but let’s put a pin in that one, okay? 🙂


Yesterday, and not for the first time, I was asked by a fellow-student at the dōjō for suggestions and exercises to develop breakfalls. I am no longer surprised by this question, for reasons that I’ll explain in a moment, but I am still very challenged by trying to answer it — or, more accurately, how to actually help improve someone’s falls in practice and not just in theory.

Around the beginning of August 2009, after I had been in LA for a few months, I encountered Erik, an Aikidōka with simply beautiful breakfalls. What was particularly amazing about them was how quiet they were. I could certainly take breakfalls at that time; what I couldn’t do was land with the softness and silence that Erik exhibited so naturally. I knew instantly that I wanted to steal this secret, not just because it looked cool, but because adopting a less bone-jarring method of falling would prolong my life in Aikidō.

Erik showed me a few exercises, very much drawn from the ukemi system of Donovan Waite Sensei. In all honesty, they had very little immediate effect. After 12–18 months, though, something slid into place and different breakfalls were “just happening” for me.

A few characteristics of these new, softer breakfalls, as they appear to me:

  1. First of all, a very strong feeling of going forward. This really is a forward roll in mid-air, with no bailing out to the side or rear in any way. This, of course, means having a sufficiently responsive body earlier in the technique so that my body is in the right place to take a safe fall at the right time.
  2. Usually, but not always, a very soft feeling in the arm that I’m going over, which is usually the one under nage’s control. I do not want stiffness there. The only exception that I can think of is when taking such a fall out of shihōnage: I do not tense my arm, but I have a much stronger feeling that there is some structure in my front arm in this situation.
  3. A very active rear arm. In my old, noisy, breakfalls, this would be the hand that does the “slapping out” against the ground to break my fall and save my torso from the main impact. In the new world, this hand still performs this function but it (a) gets to the ground much sooner than before, and (b) somehow “touches” the ground rather than “slapping” it — more like quickly establishing contact, with no rebound.
  4. Usually, but this doesn’t seem to be essential, landing with legs bent to something like 135° at the knee, rather than the straight 180° angle I was originally taught. This seems to ease impact stress on the feet.
  5. It feels very energy-efficient, and often opens up possibilities to recover quickly enough that I can reverse the technique on nage if he/she is slow in pinning me after the throw.

The end result is a breakfall that, on a good day, feels great to take and makes for very little noise or stress on the body. There’s still plenty for me to work on: I’m better on one side than the other, I definitely have bad days as well as good days, and I would still be nervous about taking such falls on less forgiving surfaces than tatami!

The question, though, I how well I can transmit this experience to those who want it for themselves. How to convey it? And can it be done without the long period of no appreciable change that I experienced?

Further notes on this topic to come as I experiment with teaching strategies.