"Aiki" vs. "Ju"
I'm a student of traditional ju-jitsu and traditional judo. It seems to me that the technical difference between ju-jitsu and judo is not as great as people would like to believe (most dangerous ju-jitsu waza are preserved in judo kata) but simply a way of approaching the same set of physical movements with a different mind set and goal. The goal of both arts is mastery of "ju", albeit for different purposes. Ju, while often translated as softness, gentleness, etc, is not this simple. It is philosophical notion in itself. Mastery over a concept therefore, is emphasised over mastery over a hollow set of physical techniques, which would limit the practitioner's application of the art, martially, socially, spiritually, etc.
My question concerns the concept of "aiki", which by the same logic is an underlying principle which aikido/jutsu practitioners seek to ultimately master rather than simply their physical manifestations, ie. techniques. How does the concept/philosophy of "aiki" differ from "ju" both in its potential martial application and on a level which is applicable both to combative and non combative scenarios?
Thanks for your time!