And from what I can gather, it's not a very common kata either, even within other Tomiki schools (mostly American ones, it seems). Which means finding more in-depth information about it is tricky, and what I can find is often inconsistent.
But this is what I know so far about why it was developed, or what we can learn from it:
Who it came from
Owaza jupon was apparently developed by Hiroaki (Riki) Kogure sometime in the 1950s, who taught in the US for a few years in the early 70s.
It seems that much of the basic Tomiki aikido training coming out of Waseda University was typically exercised with a static uke. So, in an attempt to create a more dynamic situation, Kogure pieced together some techniques that demanded more movement. (From Eric Pearson's blog.)
Okay, that makes sense in that context. It explains why we typically attack from three steps out instead of one, the way we normally would. But our school has always been a fairly dynamic one, emphasizing constant movement, etc., so I still wasn't sure how I'd benefit there.
|Ma'ai — Spacing or reach|
Another idea is that it attempted to address is people coming in from a more distant ma-ai. Up until this point, most students train with uke beginning right at the edge of our little personal bubble, always reaching out and touching hands with uke to measure prior to executing the technique. This ingrains into our subconscious a more natural sense of where the boundaries of that bubble are, and how it relates to other people (or things).
At a certain point, however—probably around first or second brown belt, and certainly by shodan— students should begin working with more natural, spontaneous attacks from all kinds of directions and distances, without all the "get ready" business, so I definitely like the idea.
|Go no sen|
Some practice it with a go-no-sen (or late) timing. While the techniques of junana hon kata are often practiced sen-no-sen timing (a middle of the spectrum, simultaneous, mutual timing), the Big 10 offers a chance to experience a more "oh, shit!" type of condition. We're caught unaware, we're unprepared, and all we can do is get out of the way.
Good idea in my book. Go-no-sen timing is often uncomfortable, a bit more frightening than the others because we're late and not in control as we'd like to be. Getting comfortable with the uncomfortable and creating harmony out of chaos is what it's all about.
For some reason I've never understood, Mr. Tomiki didn't include in his katas certain techniques that are considered something of a staple in Ueshiba schools, such as irimi nage or shizumi otoshi. The Big 10 includes them, but it also includes some repeats from the 17: shiho nage, kote gaeshi and ushiro ate. Some simply consider these versions as variations, or henka, while others find them too redundant and have replaced them altogether with different techniques.
This one always gave me some trouble. Many teach that this kata should be performed with separating, diverging centers, as opposed to the converging centers in junana hon kata. Separating, separating, always moving, moving away.
For one thing, I've had a hard time seeing all of the techniques in the Big 10 really work from a separating mindset. 1 through 4, sure, great, makes sense. But aiki nage, more commonly known as irimi nage? Maybe, I guess. But "irimi" means "entering" which seems more converging than diverging. And ushiro kubi gatame, well, I'm hanging onto the guy indefinitely.
I don't know, you could probably debate me on all that, but more importantly, I wanted to know why? Why would I want to separate? What purpose did it serve?
From a strategic point of view, I would think that just tossing uke away would only give him the opportunity to get back up and come at me again (if he didn't injure himself in the fall, which would be foolish of me to count on every time).
In fact, I've heard a number of teacher extoll the need for a more definitive approach. From classical samurai bujutsu to modern-day law enforcement, ideally we'd like to control the situation as best as we can. Pin him, lock a joint, (or from a judo perspective, choke him unconscious). Draw your wakizashi, run him through, and sever his head for a trophy. Whatever—just don't let the guy have a second shot.
So why would I just... "let go"?
This is the angle that caused a mental light bulb to go off. One thing that no other Tomiki aikido kata covers is the idea of several attackers. Now, in that case, our strategy changes somewhat.
If I'm surrounded by three or more hoodlums or ninjas or whathaveyou, I can't afford to get caught up in doing all kinds of fancy-pants techniques and locks and so forth with the first guy, because his buddies will be on my back in the blink of an eye.
So what I think people are trying to get at when they emphasize "separating" is more along the lines of "minimal engagement" and constant movement.
In other words, how can I deal with thug #1 in such a way that I avoid getting clobbered, and maybe even do something to break down his balance, without getting so preoccupied that I can't react to the next guy in line? How can I give each guy a problem to deal with without me stopping and giving everyone else a sitting target?
But here's the thing: even in a multiple attack situation, I don't always want to just throw the guy away. Sometimes, I'd like to throw, or even hold, an uke strategically—say, between me and the next attacker.
With that mindset, I see techniques like shiho nage, ushiro ate, and kote gaeshi not as mere repeats, or even henka just for the sake of being different, but as ways of possibly hanging a guy in space quickly—not letting him fall, but not letting him get back up either—with minimal commitment, to act as a sort of temporary human shield. I can, to a certain degree, control when or where he falls. Ideally, into the next guy, or at least between him and me. Ushiro kubi gatame and even irimi nage are exceptionally good for doing just that.
. . . . . .
So, is any of that what the Big 10 was created for? Don't know. Maybe, maybe not. Perhaps only Mr. Kogure knows for sure. But for me, at least the Big 10 finally makes a lot more sense in my mind. At least for now!