David Orange wrote:
So my question remains, what, exactly, differentiates aikido from sumo/jujutsu/judo, since all are based on tanren, and how does the internal pressure model explain non-contact aiki?
Sorry for jumping in here when I just have a beginner's understanding of things. It seems to me what distinguishes these and other arts from each other cannot be described in terms of principles, because each art, generally speaking, seeks to integrate every applicable principle. The difference, as I see it, rests in the differing emphases of the various arts...and that usually includes things like lineage, personality, tradition, etc. Watching a Judo video of Mifune-san I kept thinking, "that's just like 'aikido'." After seeing it I can't help but think the main difference between many arts is in who determined their names as well as other superficial details.
As for "what is Aikido" my answer is that pure aikido is the cultivation of "win-win" situations. To refine what a "win-win" situation is seems impossible to me since one has to define what is "good". It's like the folk tale of the farmer...his horse runs away; his neighbors say "what bad luck!" He says "good, bad, who knows." Later it comes back but with several wyld stallions (thank you Bill and Ted). "Oh what good luck" his neighbors say. Later his son breaks his leg trying to tame one of the new horses. "What bad luck!" Yet the broken leg prevents the military from conscripting his son and sending him to war..."how good!"... You can see where the story might go from there; the point of which is that we never fully know the ramifications of any given action until further along down the road, and even then we don't always (if we ever) know.
I suddenly feel compelled to delete this post of mine, but maybe one of you folks will be able to lend me better information...