The Axle and Torque

There are many obstacles when training in Aikido and Iaido.  The biggest one I face is the language barrier.  There are so many Japanese phrases that have approximate English translation definitions.  One of my Iaido students has been trying to teach me some Japanese, though he, himself, isn’t fluent.  He gave me a dictionary and I consult it often in an effort to gain a greater understanding.  In the process of looking up “center”, which I still haven’t found in the dictionary, I came across the word “kaitenjiku” (shaft on which something turns).  I’ve been pondering this word and its implications in Aikido and Iaido.

As an Iaidoist, the concept of kaitenjiku is more applicable to Sato, Uto, Atarito, Ryuto, or any turning technique.  Again, the head and the hips should be in alignment.  By keeping the hip and head strong, the sword is able to move faster and with more stability.  I think of a car with its wheels.  If the axle is not stable, the rotation becomes more of a wobble instead of a smooth movement.  The efficiency of the momentum is wasted and energy transfer is lost.  The same occurs with the sword.  If the center isn’t stable, the maximum transfer of energy to the tip of the sword is lost.  The kaitenjiku becomes the fulcrum or “shiten” around which the sword moves.  It is common for beginning iaidoists to lunge forward when drawing the sword and executing the first horizontal cut from seiza.  When one does this, the hip and head are no longer in alignment.  The head is closer to the target/danger, and the shiten becomes the shoulder.  By keeping the hip on top of the back knee and keeping the chin back, one maintains his center, posture, breath, and strength as well as fluid, powerful sword movement.

So far this discussion has been focusing on the concept of the axle, or kaitenjiku, but what about the tension and torque created when something is wound around that axle?  That’s when nenten comes into play.  Nenten, translated in another dictionary, means torque, or torsion.  So how does torque, or torsion apply to Aikido and Iaido?

In Muso Shinden Ryu Iaido, the draw comes from the center.  It’s as though the blade springs from one’s belly.  Many Iaidoists only use the right arm and shoulder to cut to where they integrate the wrist, elbow, and shoulder to create one motion cutting.  After I had trained for a few years in Iaido, Furuya Sensei suggested that I get a shinken.  He said he had the perfect sword for me, and when I went to class one day he presented me with a sword in shirasaya.  He wanted to see if I could draw it.  The cutting edge is thirty-three inches long.  This is an incredibly long sword.  I stretched and barely got the sword out of the saya.  “That sword is good for you.”  After training with this sword for the last six years, I have made some discoveries.  One of them relates directly to the subject of this essay.  In order to draw the sword from my center, I have to rotate my hip while completing saya biki.  My hip rotates at the base of my kaitenjiku while my head stays stable.  This creates tension and torque in my upper body.  When I release the tension in my hip, it helps move the sword through space.  Instead of just using my shoulder, elbow, and wrist to cut, I am adding another element, my hip.  I coil my body, like a spring, employ the Nenten, and release the tension in a powerful nukiutsuki.  Without the long sword, I wouldn’t need to use my hip to help draw, and the torsion would never have been created.

No matter what our goals are in life, good posture can’t hurt.  Stay relaxed, centered and focused.  Keep Training!