Nice post, Philippe. I personally see no overriding difference between "koryu", "traditional styles", "family traditional styles", and so on. The longer a 'school' has been in existence, technically, the more room there is for deviation from the original teachings. I know of a number of very ancient "traditions" which have deviated all over the place. The idea that someone is 'preserving' something unchanged from an earlier time and culture makes me wonder if we're living on the same planet.
What phyla of martial arts are you referring to by your terms traditional styles
and family traditional styles?
I think you may be missing a point that makes koryu really fascinating if you are into such things, and that is historical significance and the irrevocable shift in context brought about by the Meiji Restoration and abolition of the bushi class.
To understand koryu I think you must understand the economics of the Edo period. These entities existed because there was a market for them. Samurai were paid stipends by the government and were given social and some economic incentives to spend a portion of their money and time building "warrior virtue." Most though not all of this picture involved combative training, for which a samurai would seek (for himself or for his sons) whatever instructor or school was within his means and appropriate to his station and ambitions.
Before the Edo period, the common theory is, these arts were judged on the battlefield. During the Edo period there was rarely a battlefield, there were occasionally duels of varying levels of lethality and publicness, and there were public demonstrations. But schools kept their secrets because they were basically trade secrets. If a young warrior was being taught a way to subtly shift his weight to draw an attack that lures the opponent into a very bad position, and he gets involved in a duel in broad daylight and pulls this trick, then somebody from a rival school is going to see that and steal the trick and devise a workaround for it. The value of that teaching has just dissolved.
And in general, the koryu were evaluated on very utilitarian grounds. "Will this school give my son power that he can use in his everyday life as a 100-koku samurai?"
Mike, I think you may be saying that the reasons for secrecy among koryu and these other arts you draw a parallel to are similar. Perhaps, but i think the criteria by which they were evaluated in their time and place may be different.
When the Samurai class was abolished in 1868, the economy changed drastically and the market for martial arts was dramatically reduced. What to do with the whole "warrior thing" as Japan pressed onwards towards the future becomes the defining question of Japan for the next hundred years, obviously. What happened to koryu at this point is something that I and others find really really interesting.
Now, I've heard Ellis Amdur describe a difference between "kobudo" and "koryu" where the former is a school that is stuck in time, whereas the latter is more of a living thing that flows through time.
But IMO, koryu are taught and transmitted today with the understanding that the only set of merits by which they can be objectively judged are gone. This means that you do them because you like them and feel like you have to. You aren't going to get many chances to feed your ego, use what you have learned in a reality that it was designed to prepare you for, get paid, have women flock to you, etc etc. The only reason to do it is because you wanna do it.
Now an interesting thing about this is that, in historical situ, koryu kept their secrets because divulging them would have direct negative economic consequences. In modern times its the opposite. Why wouldn't somebody who spent 20 years training severely in some koryu jujutsu school, while trying to make enoguh money to eat teaching english in some rural town in Japan, want to put together a two-hour DVD "Inner Power of the Samurai" and sell it? Heck productize the system and get MMA trainers to come out to your gym for two-week intensive certification sessions. Why wouldn't they indeed?
At the end of the day, some of the luminaries have made the decision to offer the outside world a bit of their knowledge. But I assume that decision is informed by their understanding of what their art was in a different era.
So what i was trying to do here was just offer some thoughts on what make koryu distinct from other arts. I'd be interested in hearing about the historical context of "family traditional systems" etc which I assume was a reference to internal chinese martial arts.