André Nocquet said: "Aikido is the art of tangential action"
For those who have not seen it yet, at 20:02
"If a man attacks. I consider that man is inscribed in a sphere, as represented by Leonardo da Vinci. When the two spheres collide, it is Judo, because we hold each other. It does not happen in Aikido because we don't hold each other, so both mine and my partner's spheres are tangential. So Aikido is the art of tangential action. There is a beautiful picture to understand Aikido, watch a spiderweb. The spider is a circle and the spider stands in the center, and waits. Me too, in my circle, wait, and when someone walks into my circle, then I can act. I must wait untill another attacks and gets a little into my circle.
This is an individual practice? Yes, it is an individual practice, then I turn around the opponent and in the principle of non-opposition, Yin and Yang become complementary. This what people should understand."