Atemi, Japanese for striking. A term mostly used in grappling martial arts to distinguish between different categories of technique.

In Aikido as stated above it is generally taught to more advanced practitioners to develop the more practical application of the art. In other martial arts such as Jiu-Jitsu, Atemi is an integral part of the martial art.

Atemi can be used as a transitional move to distract the opponent while progressing to another technique, to aid kuzushi (breaking balance)so another technique such as a throw or take down to be performed, or as a technique in itself (using striking to deal with the confrontation).

To Achieve greatest effect with Atemis, Aikidoka and Jitsuka should aim their strikes at vulnerable points of the body, such as eyes, throat and for more advanced practitioners pressure points. Striking pressure points requires a high level of accuracy and can be highly dangerous, so when practicing and when using in real situations extreme caution should exercised.

In Martial arts that concentrate purely on striking, eg. Karate, exponents undergo years of knuckle conditioning to fashion their hands into weapons that can break through more protected areas of the body. This involves lots of painful training and will slowly deform your hands so I prefer accuracy over raw power.