Think of how the human body moves. Our natural movement is smooth, not jerky. We are most comfortable with smooth acceleration and smooth deceleration, not in abrupt starts and stops. We resist, instinctively, any movement that is not comfortable. When we fall, we brace ourselves and stiffen up, since we know that a hard, sharp impact is ahead. This behavior is not learned, but instinctive. But if we don't perceive danger or sudden change, we don't react or resist; our instinctive warning systems aren't activated.
How can we leverage this in aikido? In a previous blog, I wrote about "don't cut corners" with respect to our attitude and effort on embarking on the aikido path. Here I'll address some technical issues that may help in making moving our partners an easier effort. I don't take credit for this, since several aspects of this were introduced to me by my colleagues in the art. You know who you are, and I'm truly grateful for learning about much of what is below from you.
Look at the anatomy of a straight punch, the kind we usually practice in aikido. Though not quite a straight line, there is a continuous path from the spine through the back and the arm to the fist when contact is made, with no corners in that path. With a roundhouse punch or yokomen attack it is even clearer. Reflectively, if you want to control an attacker's center, or at the very least, his spine, you have to create a path to the spine from wherever you make contact that is free from corners. If you induce a corner, as is common in my practice with yokomen shihonage irimi, you disconnect from your partner and face resistance.
A senior instructor suggests to "lead out the end of the jo". The jo is the longstaff we use in aikido practice. If you want to move a jo through the air like an airplane, you can only move in arcs. Similarly, to move your attacker by "leading out the end of the jo", you have to move the point of attack in arcs -- don't cut corners. My experience is that if you consider the straight line through the shoulders as a jo, use the arms to lead that "jo" out through it's ends, and you face very little resistance. If you manipulate that axis, you connect with the spine, which is a good initial surrogate for the center, and can manipulate the body reasonably easily as a result. At Frederick MD, we have been experimenting with this concept for the last 6 months, with some success.
Let me attempt to provide an example. Let's look at yokomen shihonage irimi The arm comes in at an arc. As we block and pick the arm up, we continue that arc taking the arm up while turning the body. If you get eager to turn uke by creating a corner at the shoulder, the arm goes across uke's body but uke stops moving. He naturally resists since this feels unnatural to the uke. If you, as nage, maintain the arc from the neck through the shoulder to the wrist, you find that uke resists far less, and often cannot resist the turn as shihonage is applied.
A natural question to ask is, how do we reconcile nikkyo and sankyo to this concept. We are mostly taught that nikkyo and sankyo are defined by a physical orientation defined by corners; the proverbial Z-shape for nikkyo and the right-angled arm for sankyo. My personal thoughts are that these morphological definitions are limiting and I have seen that merely achieving these shapes isn't enough and can be resisted reasonably easily once the pain is accepted. My investigation continues into how to most effectively control uke's center through these joint "locks".
I will admit that explaining aikido technique in writing is infinitely difficult since there is so much feeling and physical negotiation going on during a technique. One of the better descriptions of "don't cut corners" can be found in the famous illustrations in Westbrook and Ratti's book "Aikido and the Dynamic Sphere". As another senior instructor recently said, we all need to research the art to figure out how the fundamental aspects are put together into effective technique. Feel free to experiment in your local laboratories to see if this concept can work for you.