Aikido is a traditional Japanese martial art created by Morihei Ueshiba (O-Sensei) in the early 20th century. As the physical practice of philosophical principles developed by O-Sensei, Aikido strives for the ultimate goal of peaceful resolution rather than defeat. Composed of three Japanese characters: Ai, meaning harmony; Ki, spirit or energy; and Do, the path or the way, the word Aikido thus signifies the 'Way of Unifying Life Energy'. In this regard, O-Sensei created a martial art in which the preservation of one's attacker is equally important as one's own self defense.
Aikido is more than the study of physical techniques; proper etiquette, attitude and behavior are also stressed. The basic movements of Aikido are circular in nature. The Aikidoist trains to harmonize with, rather than confront an aggressive line of force and converts it into a circular motion that renders attackers helpless. The Aikidoist trains to apply various wristlocks, arm pins or unbalancing throws to subdue and neutralize attackers without serious injury. Such practice is done in tandem with learning the art of falling, or 'ukemi', which trains the body and mind to receive such techniques in a safe manner.
Aikido is not a sport and hence there are no competitive tournaments. Rather, by cooperative training, the Aikidoist betters oneself without belittling others, without the intention of harm or fear of injury. As traditional Japanese budo, Aikido maintains the qualities of martial spirit, effective technique and intense training. This, coupled with the premise of mutual respect and caring, and the important balance between attacker and defender, encourages the spirit of O-Sensei's desire for universal peace. -excerpt from USAF website