Re: How do i know when i can feel KI?
Never mind about ki. Ki is a modified version of the emperor's suit of clothes. It may exist. It may not exist. But many people can't or don't perceive it, and (unlike in the old story) that doesn't make them dolts. More likely, it makes them honest.
Claiming to see something that you can't really see (clothes or ki) is self-deception and attempted deception of others. Trying to see something that may not be there, or that you may not be equipped to perceive (not now or not ever, doesn't matter) is a vain effort and a waste of time. Doing tricks that don't actually prove anything, and then nodding your head and agreeing that they prove the existence of something that may not exist, is charlatanry.
You don't need ki. Just train and focus on less sexy, less mystical-sounding goals: correct execution, correct body movement. These are things that you can't sit around and talk about and make unfalsifiable claims about; you have to get your butt on the mat and actually do something, and try for a long long time to get it right, and never be able to stop trying. Maybe ki exists, and if so, maybe it'll come into your aikido some day. If it did, and you didn't know it, if didn't yell out, "Aha! Ki!", would it matter?
Ki may exist, but if it does, I'm convinced you won't find it by chasing it or peering at it or telling yourself that yes, you really do feel it. And if you feel that you're lacking something because you can't see these amazing clothes that everyone's talking about, well, you need to get over that.