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Old 03-22-2005, 02:33 PM   #67
Brion Toss
Dojo: Aikido Port Townsend
Location: Port Townsend, Wa.
Join Date: Jul 2003
Posts: 104
Re: Tenkan and Centrifugal Force

Mike Sigman wrote:
OK, I see where you're coming from, but I think you're missing the point. When you "pivot", that's the tenkan, which has the point of moving out of the line of attack and placing your body in a position to go somewhat with the attack ("aiki"). As you begin to "lead", in the technique you're mentioning, you are indeed making use of "centrifugal force".... that's what you're saying. I don't have a problem with that, but as you lead into a technique (the lead into kote gaeshi, in this example), you are already past the tenkan. That's why I pointed out that a tenkan can just as easily lead into a kokyu throw as into a throw that uses "centrifugal force". The tenkan is the turn that initially allows you to avoid the line of attack... all else is the lead and then the technique. Even if I choose to go into Sayu Nage at that point there is a slight lead/entry (not really involving centrifugal force) into an off-balance direction and then the consummation of technique. But the tenkan was the "pivot" that took me off the line of attack, Bill, not the lead or the actual technique.

Insofar as the physics goes, you can see that it's not the centrifugal force.... however, the physics is indeed interesting. Tohei actually does a pretty good job of trying to explain the application of forces through his Ki paradigm, but he's not clear enough so that it's obvious what he's saying. The essential "force" in Aikido that is always spoken of in relation to "Ki" is the force of "kokyu ryoku", or "jin" (sometimes spelled "jing") in Chinese. It's the resisting force that Tohei exhibits when he is standing on one leg (or both legs, or lying down, or from behind, etc.... you can manifest this one force in any direction, but it's too complicated for this post).

The main idea is that you can manifest this force at will in the direction you want it to be in. For example, if someone pushes against my chest, I may want to manifest this kokyu force at my chest so he can't push me over, thereby impressing onlookers. In real Aikido, of course, we would never deliberately resist the force, but would immediately move offline or go immediately with the force and begin a technique into a direction where the pusher has no power (there are a number of these). BTW, please forgive the pedantry... I actually have a point I'm working toward.

So when an opponent grabs my wrist, I enter while turning (that's the tenkan) and I must manifest this basic kokyu force of Aikido into a direction that suitably begins the lead-into-technique. The lead into the technique of kote gaeshi involves you forming the kokyu force into one direction, up, then over (every bit of the movement is powered by kokyu force). It often looks like a sudden, straight technique but if you analyze the directional changes the kokyu forces go through (if you did it correctly), those forces make a circle. You may have included another circle horizontally (here's your beloved centrifugal force ), but the leading force you use to effect putting your partner into a centrifugal arc is also part of the kokyu power you must manifest throughout the technique.

In other words, the importance of entry and technique is just as much your ability to manifest kokyu power in relation to the opponent as it's important to do the technique. This is true of ALL techniques involving Ki/Kokyu as O-Sensei, Tohei, et al mean it, and it is considered quite different from the normal use of strength and just "technique" involving centrifugal force. Most people practicing Aikido use normal force and focus on "technique" while never developing useable kokyu force throughout all directions of movement. The Aiki Taiso at the beginnings of classes are originally meant to warm you up in the use of kokyu power throughout the entire range of various movements.

The lead into Sayu Nage (as another example) from tenkan is the same universal idea... you move off-line, immediately match your "ki" to the opponent's grab as you begin the "lead" of up and over (another circle!!!) with your kokyu power, driven by your hips and hara (the hara actually controls the direction of the kokyu force).

That's more the intriguing part of the physics, IMO, Bill.


Mike Sigman
I like that. I really like that. Thank you for an information-rich posting, Mike.
Brion Toss
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