Aikido, Japanese aikidō (“way of harmonizing energy”), martial art, and self-defense system that resembles the fighting methods of jujitsu and judo in its use of twisting and throwing techniques and in its aim of turning an attacker’s strength and momentum against himself. Pressure on vital nerve centers is also used. Aikido practitioners train to subdue, rather than maim or kill, but many of its movements can nevertheless be deadly. Aikido especially emphasizes the importance of achieving complete mental calm and control of one’s own body to master an opponent’s attack. As in other martial arts, the development of courtesy and respect is an integral part of aikido training.