Aikido is a Japanese martial-art derived primarily from forms of traditional Jiu-Jitsu (the martial techniques and schools of the Samurai). Sometimes called the "Modern Martial Art", Aikido differs greatly from all other martial arts systems in a number of key ways.
In Aikido, cooperation and harmony are more important than aggression; timing and control more important than strength. Aikido is non-competitive and non-violent. Nevertheless, with the development of basic techniques, Aikido provides a very powerful means of self-defense.
Techniques in Aikido are characterized by circular and spherical movements which are used to redirect an opponent's force. Aikido explores how an opponent's attack can be grounded and controlled without strength. Finally, and perhaps most importantly, at its highest level, Aikido seeks to protect even the attacker from harm, and to end the violence rather than simply win the fight.
Aikido practitioners, called Aikidoka, seek to engage a violent opponent in a way that changes their mind, while valuing to the largest extent possible the desire to protect their physical selves from harm. Aikido explicitly seeks to understand and apply the concept, so important in modern social life, of "minimum use of force".
Several forms of Aikido have evolved since founder Morihei Ueshiba developed the foundation concepts of Aikido. Variations include the degree to which esoteric concepts such as Chi are studied, incorporating breathing exercises and physical sensitivity, as well as in pedagogical approaches and teaching style. All of them, however, use a cooperative approach to training techniques, stressing a certain degree of, if not gentleness, then at least concern and awareness of partner safety.
The Yoshinkan style of Aikido, developed by Ueshiba student Gozo Shioda, sought to modernize the teaching curriculum. Originally developed for a Tokyo Riot Police course, the teaching system sought to permit students, learning from teachers and engaging in practice, to rapidly acquire proficiency in the fundamentals of Aikido technique.
Disarmy dojos engaged in Aikido study will take this evolution in training one step further, incorporating study in ethics and legal issues with training in conflict resolution and crisis response. Teaching pedagogy and curriculum will be developed to support the didactic needs of such schools, clubs and students.
From Wikipedia intro:
Aikido (合気道 Aikidō) is a Japanese martial art developed by Morihei Ueshiba as a synthesis of his martial studies, philosophy, and religious beliefs. Aikido is often translated as "the Way of unifying (with) life energy" or as "the Way of harmonious spirit." Ueshiba's goal was to create an art that practitioners could use to defend themselves while also protecting their attacker from injury.