Re: Judo and IP/IS
I would like to note that to my limited knowledge there are no references in IS in Judo literature besides the one mentioned by feldenkrais and the other in Harrison's book but these are nothing but hints and in no way can prove that there was a consistent method of cultivation of IS.
Now it could be possible that if someone spent sufficient time practicing an "external" art that he could discover something "internal" that could be further developed, but this would be a matter of chance and not easily replicated. Maybe that was the case with Mifune as even if he was not very skillful in IS according to some, the way he moves is of a different quality than many excellent Judo players, powerful, explosive with excellent technique.
Another reference that might be of interest can be found by T.P.Leggett who included in his book 'Zen and the ways"a few references to ki from some Ju jutsu scrolls, the Yasenkana from Hakuin that was again included whole in "The Tiger's cave", a reference of how to coordinate breath with movement by performing simple tasks like polishing a table and some photographs of stretching maybe from a chinese scroll that described a sort of visualization.
Of course Leggett was a man of broad knowledge and the above references came not from his books on Judo but in a different context however they address the subject of ki and breath training to some extent which i suppose belongs in the same sphere with IS, but this information comes not from Judo but Jujutsu. Now again the origins of Judo were two Jujutsu schools and even if we admit that those schools had no IS to offer to their offspring this did not stop Judo from dominating other Jujutsu schools (in those famous matches ) that should have some IS
Life is a bitch
Just my 2 cent
What is your aspect?