Harry sensei says that Aikido is not circle, it is a spiral, and since it is a spiral, it is infinite. it is infinitely expanding as it is infinitely contracting. Since we are into nanotechnology, we can assume that the spiral circles we draw can spiral to nano level.
Why not straight line? Why Aikido explains everything in circles? Think for yourself, does anything in nature travels in a straight trajectory? As far as my knowledge is concerned, nothing. we all move in an indefinite pattern, look at an ant, an ant never moves in a straight line. Trees are never straight. Melons are never perfectly round either.
So what Aikido aims is to move in a round manner, not in circles, because if you do more in a circle, in a hypothetical attack situation, you come back to the point where you started, right into the punch.
So in a spiral, circular manner, the travel will either go out, if it is a punch, depletes the energy by means of an outward spiral, or draws the energy inwards, merging the attacker’s centre into ours, which results in a sensation of harmony.
This principles does not always works in a fighting situation, where the attacker is hell bent in causing hurt to us. In a fight, the situation is many a times linear, the line of attack is so intense we can barely get out of the way of hurt, let alone do a decent tenkan or irimi. Sometimes what we practice in the dojo simply does not work.
The point is to remain circular in our thinking. We got to look for alternative ways, solutions to the situation. The attack might not have materialised if we had not taken a shortcut, which coincidentally is more direct often straight route from point A to B. Even if we were met with aggression, we still have to think of a way out, and not meet violence with violence. Aikido is a stereotypical art of ‘Peace’ simply because we are trained to stall violence, let the aggression bleed itself out in a series of circular, spiral motion, upwards, downwards, outwards and/or inwards. Always circular, but never a circle.