The purpose of kata isn't just to teach a few moves. In fact, frequently by the time a student learns a kata they already know how to do all of the techniques in that kata. It turns out that kata is a sneaky-efficient method of brainwashing a student so that they think about the subject the same way that the creator of the kata thought about the subject.
Take the Kodokan's Nagenokata for example. By the time most students get around to playing with nagenokata (just before a shodan test usually :-) they have either already learned the individual techniques or the techniques are trivial variants of something they already know. So, what does learning nagenokata do for the student that already knows that set of techniques?
It enforces/insures that the student thinks about those techniques in a certain way.
For instance...
Nagenokata teaches the student to think in terms of the traditional Kodokan divisions of throws - i.e. tewaza, ashiwaza, koshiwaza.
Nagenokata suggests to students that some techniques (like sacrifices) are more 'advanced' than others
Nagenokata teaches students to value large-amplitude ippons to a larger extent than small takedowns.
I'm sure that given a 10 minute headstart, you could come up with at least a couple more examples of the meta-knowledge'that is encoded in kata and enforced by its practice.
But...
What if there was a teacher that didn't especially care if his students thought about nagewaza in those three groups? What if an instructor wanted a student to value small, energy-efficient techniques over the big ippons? What would stop some free-minded instructor from saying that their club-version of Nagenokata would consist of (for instance)
3 footsweeps
3 two-legged hipthrows
3 techniques named 'guruma'
3 techniques named 'otoshi'
And 3 sacrifices
Such a fluctuation of the technique selection for nagenokata would change the meta-message conveyed by the kata. This club kata would (among other things) place more emphasis on easier hipthrows, enforce the guruma-otoshi concept especially among the hand throws and leg throws. And reduce the feeling that the sacrifices are more important than the other sorts of throws.
Take the Kodokan's Nagenokata for example. By the time most students get around to playing with nagenokata (just before a shodan test usually :-) they have either already learned the individual techniques or the techniques are trivial variants of something they already know. So, what does learning nagenokata do for the student that already knows that set of techniques?
It enforces/insures that the student thinks about those techniques in a certain way.
For instance...
Nagenokata teaches the student to think in terms of the traditional Kodokan divisions of throws - i.e. tewaza, ashiwaza, koshiwaza.
Nagenokata suggests to students that some techniques (like sacrifices) are more 'advanced' than others
Nagenokata teaches students to value large-amplitude ippons to a larger extent than small takedowns.
I'm sure that given a 10 minute headstart, you could come up with at least a couple more examples of the meta-knowledge'that is encoded in kata and enforced by its practice.
But...
What if there was a teacher that didn't especially care if his students thought about nagewaza in those three groups? What if an instructor wanted a student to value small, energy-efficient techniques over the big ippons? What would stop some free-minded instructor from saying that their club-version of Nagenokata would consist of (for instance)
3 footsweeps
3 two-legged hipthrows
3 techniques named 'guruma'
3 techniques named 'otoshi'
And 3 sacrifices
Such a fluctuation of the technique selection for nagenokata would change the meta-message conveyed by the kata. This club kata would (among other things) place more emphasis on easier hipthrows, enforce the guruma-otoshi concept especially among the hand throws and leg throws. And reduce the feeling that the sacrifices are more important than the other sorts of throws.
