Interesting topic Jim.
In my experience I have seen that many top masters do have a real grasp of the application side of kata. You will have experienced this training on the ITKF camps. Sensei Naito in particular would get the class to perform application to kata's in a practical manner rather than sticking to the regular embusen for example.
I think this has less to do with whether 'secrets' were passed on than the time modern karateka dedicate to the study of this stuff.Remember people didn't watch tv, play on their playstation etc in Funakoshi's time and it is likely that karateka would hang out together working these things out when not in the dojo.
I remember doing a full breakdown of Jitte like this a few years ago in Edinburgh .Sensei Naito went over the Kata in it's normal form first, then altered the body position ( Angles and Stances etc) for many of the blocking techniques, and got the class to work in partners applying realistic blocks and counters.This involved a lot more use of sabaki and shorter punches ( Ura Tsuki etc) than the 'basic' static application which many have experienced.
Whether or not this was handed down through Funakoshi / Nakayama lines as a standard is not so clear. I understand that Kata bunkai and bunkai omote are things which Sensei Naito and Sensei Shirai would practice and develop together quite a lot- similar to the old days.When I was in these classes I really got a feeling that the Sensei had a deep, inside out, kind of understanding of the kata and its applications.
I think that this kind of study and research of the application side of the techniques is a form of natural progression for masters at that level, but there are probably only a few people who really understand the kata as deep as this.It is great that we in ITKF have the chance to experience this depth of understanding,even if only for a few hours.I reckon it depends on how much time you have to develop applications to the moves of the kata outside of the hours you already spend training ( After all we all have lives , tv's playstations etc...right ?! )
Another thing to remember is that the one of the strong points of JKA karate when it started to be spread around the world was the standardisation of techniques.This meant that the guy training under a JKA instructor in 1965 in South Africa was doing the same kata as taught in the JKA instructors class in Tokyo.The fact that Sensei Nakayama was smart enough to realise that he could not send individual instructors to all corners of the world doing different things may account for why they concentrated much more on getting the fundamental kata spot on rather than diversifying into too much bunkai which may have led to alterations in the standard form. This also contributed to the strength of JKA karate as an association up to the time of his death.
As for me, I would be happy if I could work out how to do one gyaku-tzuki properly!!
