The short answer: "ki" is gravity, structure, and proper use of tension and inertia.
Yep.
I watched a Windsong Dojo (Oklahoma City) seminar in which George ledyard (aikido dude of some reknown) gave us an explanation in which he used a Chinese medicine phrase which had everyone on the mat cringing and squirming as they knelt watching and waiting.
Here's George's info:
http://asu.org/senior_instructors/george-ledyard-sensei/
George said, "At the first instant, when you establish the connection to uke, you should already have, or immediately should, open up your heart chakra."
People were like... really. Open up your heart chakra. WTF is a heart chakra and how do I find one in Oklahoma Arkansas or Texas.
George had run across this before and while he delivered the line straight-faced, deadpan... he broke into a grin and laughing, said, "Sorry. I mean, stand up straight, pull your shoulders back and grab good posture. Same thing."
He went on to describe how many of the Chinese medicine terminology... when translated from what they say... into what they mean... makes perfect sense from a Western science, physical, measurable world, point of view. IF you can get it translated, which is the hard part.
I'm with you, Gerry. For me, I call it, feel it, describe it as Ki is when you do it right, and everything falls into place and everything is in its place . The technique comes off without hardly any noticeable effort on tori's (nage's) part, seeming to effortlessly send uke across the room with the artist seeming to hardly move. Or, if projection isn't the goal, to drop the person at the artist's feet, crumpled into a submitting heap, unable to continue the attack for whichever reason befell them.
It's not the Force at all. Though it might be fun to "Get the glow!" This last for you The Last Dragon fans... I've felt it, and it is a neat feeling, simple to explain, hard to understand.
Your posture and position is correct, uke has lost theirs and being disadvantaged, the minimal effort (force) you exert in this or that vector causes a chain of events magnified by uke's own musculoskeletal system, gravity or both, and ... something happens which is well nigh perfect technique.
Just the other day I was involved in a pre-class randori session with my nidan student, who was amping the speed up. A self-test exercise I suppose. It was fun, and we were both laughing as things flashed into place, almost, and were defeated and dealt with faster and faster.
As an aside, you know the problem with fast practice? K.E. = (0.5)M times V(squared) Speed kills, because it's an exponential increasor of the kinetic energy involved... plus, you can only comprehend things as fast as you can take in the info and evaluate it.
Anyway, we're pretty close to "This is getting stupid" speed, but pretty far from DropBear's "Full Noise" or as I call it "Full-tilt boogie" speed.... still, he was going too fast for him. In my mind,t hat's OK as he needed to find that out and I wasn't going to hurt him, intentionally anyway. No, that's not foreshadowing.
So, there's this Tomiki technique called Gaden-ate (low strike) which is a misnomer of naming convention, as it's less a strike in what we Westerners think of as a strike than it is... maybe a hockey check into the board? A sideways belly-bump? It is similar in position to, but not execution of, a sukui-nage (scoop throw) for those of you who know that. Instead of scooping them up and dropping them on their back, which is fun in my opinion... you don't scoop at all, as it's considered bad form, you merely check them laterally to their back corner -- which you've already broken their posture and the drop is just an uncontrolled backfall into their away from torie back corner. Usually gentle. Usually.
Back to my guy & I... we're moving too fast for safety, though we Are having fun, and he steps across me attempting to either get across my face for Gyakugamae-ate (what we call the eye-flash, then head control backfall takedown that a lot of styles do) or if he gets my hand/arm controlled the wakigatame arm bar. I felt him and not thinking about it put my arm against his chest and slid across and into him for the gaden-ate.
Boom!
So, I checked him with my bod against his, no big deal 240 vs. 230 (lbs), I had neatly tucked him into his right rear corner and his posture was blown before he realized it and his feet broke traction-friction with the mat. Up he went and off he flew. What I did to him was maybe worth about a 3, maybe 4 foot of flight distance.
Problem was, his own body reacted... badly.. to the throw, and being surprised he didn't open, relax and accept the fall. Oops. His abs tensed up, his head snapped around looking for the floor and he snapped his body open into a sprawled falling osture. Each and all of those vectors accentuaded the slight Up vector I'd given him as he cleared my leg, which had been behind his legs. So, instead of 3, 4 feet.... He went 8 or 10. We walked the distance off afterwards. To me, it didn't feel like anything much, no sense of expended effort, no exertion, no muscular thrust involved. To him, he said it was like getting hit by a car whose front bumper was covered in pillows.
I took offense at that last bit, I admit. I am not covered in pillows, nor do I resemble a pillow in any way, shape or form.
Still, for me... that was Ki.
