In Japanese martial arts, the term atemi (当て身, atemi?) designates blows to the body,  as opposed to twisting of joints, strangleholds, holding techniques and throws. Atemi can be delivered by any part of the body to any part of the opponents body. They can be percussive or use ‘soft’ power. Karate is a typical martial art focusing on percussive atemi. The location of nerve and pressure points, such as might be used for certain acupressure methods, also often informs the choice of targets for atemi (see kyusho-jitsu).
Some strikes against vital parts of the body can kill or incapacitate the opponent: on the solar plexus, at the temple, under the nose, in the eyes, genitals, or under the chin. Traditional Japanese martial arts (the ancestors of judo, jujutsu and aikido) do not commonly practice atemi, since they were supposed to be used on the battlefield against armoured opponents. However, there are certain exceptions.
Atemi can be complete techniques in and of themselves, but are also often used to briefly break an opponent’s balance (see kuzushi) or resolve. (For example, this is the predominant usage of atemi in aikido.)  A painful but non-fatal blow to an area such as the eyes, face, or some vulnerable part of the abdomen can open the way for a more damaging technique, such as a throw or joint lock. Even if the blow does not land, the opponent can be distracted, and may instinctively contort their body (e.g., jerking their head back from a face strike) in such a way that they lose their balance.
The development of atemi techniques arises from the evolution of the Japanese martial arts, in particular jujutsu. Early styles of jujutsu from Sengoku-era Japan were created as a means of unarmed combat for a samurai who had lost his weapons on the battlefield. The purpose of jujutsu was to disarm the opponent and use their own weapon against them. As such, strikes to the body were limited as the intended victim would have been wearing extensive body armour. However, in later styles of jujutsu from Edo-period Japan empty-handed strikes to the body became more common as full-scale military engagement began to decline. This meant that the jujutsu practitioner’s opponent would not have been wearing armour and the vital points that form the crux of atemi-waza were more exposed. Thus atemi began to play a pivotal role in unarmed killing and restraining techniques.
The use of striking in the performance of Aikido waza or applied technique is not well documented and is even the source of quite a bit of conflicting information. Saotome Sensei has made it quite clear that O-Sensei taught that atemi in Aikido was at the heart of the practice. Yet other instructors have been known to say there are no strikes in Aikido. A number of practitioners believe that Aikido’s peaceful intent is lost when atemi is used yet those who have worked to preserve the martial integrity of the art know from experience that any experienced attacker will defeat Aikido techniques if there is no use of atemi. Even those who feel that use of atemi is perfectly appropriate in Aikido waza may not have considered in any systematic manner the various ways in which it is actually utilized in the art.
The use of strikes in Aikido manifests itself in three main ways (Each of these can be further broken down into more precise description.)
A Strike as a Technique in Itself
A Strike as a Means to Facilitate Another Technique
The “Not Striking of Striking”
The use of atemi as techniques in themselves, in other words to end the confrontation without need for any other additional application, is as a means of creating physical dysfunction. This can range from strikes which attack the vital organs and are designed to kill to strikes which are targeted at specific limbs and can end an attack by making it impossible for the attacker to continue. This could include crippling blows or strikes which are meant to deliver enough impact to render an attacker unconscious. The use of atemi alone to end a confrontation is not generally studied by aikidoka of the post-war styles and most of the practitioners who have a working knowledge of this aspect of the art acquired their knowledge by way of training in some other striking oriented art. The use of strikes in this manner is generally considered the option of last resort in Aikido because of the emphasis on non-violence. The Aikido ideal is to end a confrontation without inflicting serious injury on the attacker. So this area of study is, for better or for worse, de-emphasized in most Aikido training.
When strikes are used as a means to accomplish a different non-impact technique it can be executed in two different manners. In the first case an atemi can be applied in order to cause intense pain and therefore create a shift in the resistive energy of the attacker (this could be accomplished with or without injury based on what type of strike were used and at which of the above targets). The moment the attacker shifts his attention and therefore his Ki to the site of the pain his resistance to the main technique being attempted tends to diminish drastically. This use of atemi is generally considered by most Aikido practitioners to be the proper one if strikes will be used at all. The drawback is that techniques that rely solely on pain are quite unreliable. A seriously motivated attacker simply doesn’t notice and that means that there is no shift of attention. So choosing to target atemi to non-injurious vital points can increase the risk of failure in a self-defense situation.
Another way in which impact can be used as a means to accomplish a different technique is by using strikes not for injury or pain, although those might possibly be a by-product, but to change the physical alignment of a resistant attacker. Frequently when an opponent has stopped a technique, it is close enough to success that switching to a variation is not necessary. The simple application of impact, such as a knee strike to the back of the upper thigh when an attacker resists a kokyunage, can change the alignment of the attacker sufficiently to free up the blocked energy of the technique. No pain or dysfunction is necessary in this type of impact delivery. It simply alters the structure.
The final aspect of the use of atemi in Aikido falls within what I call the “not striking of striking”. This is the use of a strike with no necessity or expectation (on the part of the person delivering the atemi) that the strike actually make contact. This is the type of atemi which many Aikidoka favor while not understanding that for effective use of this atemi to be made, mastery of the actual impact techniques previously described needs to be attained. This is the “energetic ” use of atemi and the attacker must really believe that the true strike were being delivered and feel the necessity of putting his attention on it.
Imagine that you are standing behind a perfectly clear sheet of Plexiglas and someone throws a baseball at your head. If the throw were done powerfully, with speed you would cringe and duck even if you knew the Plexiglas were there. If the throw were done by simply lofting the ball you would probably not react at all. The “not striking” use of atemi must have all the energy and potential of a real strike or it will not create the effect on the partner, which it is designed to accomplish. The weak atemi thrown by many Aikido practitioners will simply have no effect on a motivated and trained attacker.
The “not striking of striking” atemi can be used as a distraction technique in the manner described previously. To accomplish distraction and its attendant shift in resistive energy it is only necessary that the attacker shift his attention. This might come about because the strike connected and caused pain enough to register in his consciousness or it might occur when the attacker uses a block to deal with the strike and prevent impact.
Anyone who has had occasion to apply Aikido techniques on a really resistant subject as in police application knows how hard it actually is to get a technique on someone intent on countering it. We train to maintain connection but a real attacker will attempt to break with you the instant that he doesn’t feel things are going his way. It is necessary to get the attacker to create an opening for establishing connection by delivering an atemi, which forces the attacker to block. The Aikido technique can then possibly be run on the blocking arm rather than on the arm or leg, which had delivered the primary attack. Once again, it is possible that the atemi will hit but it is often not required, as it is much easier to get a connection with some part of an attacker’s body when they commit to defense than when they are throwing an attack.
Finally, the aspect of striking, which is most misunderstood outside of Aikido circles, is the so-called “touchless throw”. Every interaction in Aikido contains many different possibilities. Most of the time in Aikido practice the strikes are implicit rather than explicit. One can do a whole class and not see any overt strikes. This is because, if well trained, both partners know where the strikes could be and do not do anything within the interaction, which would require that, the hidden strikes become manifest. But in the “touchless throw” we see the “not striking of striking” used in its most artful guise. This is accomplished by subtly changing the timing of a strike. The strike needs to be just fast enough that the attacker can not avoid or block it but is just slow enough that the attacker can respond to it by breaking his posture and taking a fall in order not to be hit. The emphasis on this type of interaction is unique to Aikido. It is actually a valid martial interaction in a type of coded form. An uke trained in the use of strikes as throws will be airborne the instant the strike is perceived.
This can give an onlooker the impression that the attacker is throwing him self. At that point he either decides what he is seeing is bogus and involves the cooperation of both partners or, if mystically inclined, he believes that he is seeing people being thrown energetically, without the need for actual physical contact or force. In fact on one level each of these points of view is true but not for the reasons they would think. The point is that here we are looking at a form of Aikido interaction which doesn’t normally exist outside of the dojo. If one tried to throw an untrained partner without touching him it would merely manifest itself as a strike which hit. The partner would not understand that the agreement exists that I run the strike in just such a way that there is just one “out”, to take the fall.
There are probably other, more subtle ways in which Aikido utilizes atemi but the main ones are covered here. If one expands the definition of atemi from striking to include anything which nage does to catch the mind of the partner for a split second, then a whole new area of discussion opens up. One of my dear Aikido friends was fond of planting a big kiss on your cheek just before hurling you with her iriminage. It is indicative of the varied approaches to Aikido practice that many students seem to pick only certain of these aspects to incorporate in their technical repertoire. But as soon as one is interested in application of the Aikido techniques outside the controlled environment of the dojo it is necessary to put some emphasis on understanding each of these applications.