Atemi is a big thing, so much so that you can find a topic in wikipedia, http://en.wikipedia.org/wiki/Atemi
Harry sensei, practice little or no atemi, and I’m beginning to understand why.
A couple of training back, I was practicing with Matthias and Cristian, and we came to a Kata–tori technique, which i responded with a tenkan, to displace my uke, following a reversal, side stepping out, causing my uke to fall.
Matthias tried that and it didn’t quite work out, when Cristian did the same thing, he did an atemi before side stepping out, as part of the strategy to displace and cause the uke to fall. When i did the same thing, i find the atemi unnecessary by the time i side step out, my uke, is already displaced, and a fall is inevitable
And when Cristian was the nage, and i was his uke, i got a sense of why an atemi is necessary for him and not so for me. He did an atemi, as in the process of side stepping out, our body position brings us in front of our uke, hence in order for the nage to prevent the uke from counter striking, the nage proposed an atemi before finally displacing the uke.
What i felt was the atemi, as a prelude to the fall, actually gives your opponent a heavy hint of what is to expect next, and what your uke can expect, he can deal with. So the equation is prior to a ukemi, is an atemi. if an atemi is thrown, uh-oh! coup-de-grace!
If you are able to keep your uke in motion, unsettled, then to throw an atemi, will sometimes stop the flow, and give the advantage to your uke, to swing the situation around, to his advantage.
When I did the technique again, i realised that there was sufficient distance, my uke will be displace enough to fall, and if my uke doesn’t fall, i can quickly mutate the technique into something else by moving again, with no stoppages.
The hindsight of an atemi strategy is one of deceit. A form of cheap-shot at your opponent, because somehow or rather, your technique is weak, and in order to bring a better opponent down, you have to steal a strike against the person, to achieve superiority. so if we take away the atemi, and let the technique flow as it is, the truth is, it will not be as effective. Hence the atemi becomes and integral strategy which will fail utterly, if your opponent is very skilled and very fast.
Against a fast opponent, we need to bleed out the person’s speed and energy, the inherent circular movement of Aikido, typically keeps an opponent guessing where the end is, an application of an atemi, is a dead giveaway of what will be coming next, and you can bet you life that your opponent is waiting for you, at the other side prepared for you when your atemi ends.