The Earth is round for a reason. The planets rotate around the Sun for a reason.
In Aikido, we do turns after turns for a reason.
The reason is the curve.
Why is life so angst to some and so wonderfully mysterious to others? We like predictability, but all we get is surprises, and more surprises after surprises! This is the Case of the Curve. Or for some, the Curse of the Curve.
In Aikido and some other martial arts, we use turning as a strategy to hide, conceal our moves against our opponents. Tenkan is one of such move, that allows us to get very close to our opponents, at the same time shielding our hands and potential weapons. We can hide our plans.
The curve will also starve out our opponent’s energy. Instead of absorbing the linear force, with force, or direct absorption, we turn away from or towards the energy, literally rolling with the punches. This takes tremendous courage and timing, which can only be achieved with practice. So you don’t have to be very, very fit to use Aikido well. Surely the by-product of a well-trained Aikidoka is fitness, but no Aikidoka is super fit to a Olympiad level. We need a good balance of everything.
Most importantly, we need to understand the principles of rotation, curvature and the physics of roundness very well. Your opponent cannot oppose you if they cannot feel your strength, which is always rolling. If it is linear, they can track and trap it, for a linear trajectory is often predictable. No one can see a turn, very much like you cannot see beyond the horizon. And it is in the horizon where we lie in waiting, for our unsuspecting opponent to walk into our plans.
And the curve is non-confrontational. Of course having said that, it is not a kind of wishy-washy. that is not a disciplined use of the curve. that is simply being wishy-washy. If you are disciplined in the application of the curve, you will not weasel out of a difficult situation, in fact you will never find yourself in a difficult situation, because when you are rolling and bending intimately with the situation, you will be able to detect hostility even before it happen, and diffuse it, or walk away from it, diplomatically, before it becomes uncontrollable.
Learn the roll, the curve. Everything rotates, and make sure that when it turns, it turns towards you in a favourable outcome. and when the outcome is unfavourable, turn away from it just as quickly. Either way, Day will turn into Night, and Night will turn into day, just as much as good will turn bad and bad will eventually turn good. Just keep rolling along.