It is a fighting style founded by Morihei Ueshiba with main influences by Daito-Ryu Aiki-Jujutsu.
Its name may be translated as the Way (Do) of Harmony (Ai) with Universal Energy (Ki), where Ki (or Qi) designs a natural energy which flows within the human body.
It is essentially a defensive style whose goal is not to destroy the adversary, but to neutralize his attack by using his energy against himself.
Aikido techniques are represented by circular and avoidance movements followed by joint locks and projections. Atemis (strikes) may be also performed to allow a better execution of those techniques. The practitioner seeks to carry out these movements by replacing his muscular strength with the Qi.
Instead of the "push when pulled and pull when pushed" rule in Judo, Aikido principle can be defined as "enter when pulled, and turn when pushed".
Although Aikido features a refined technique, with movements that require minimal effort, it may take relatively long time for a beginner to develop.
Aikido is the basis for mastery and immobilization techniques of many police officers corps.
There are no competitions in Aikido, in order not to stimulate feelings of power that would hinder the spiritual development of the individual.
Ueshiba began to develop Aikido in the late 1920s. It was recognized by the Japanese government in 1940 under the name of Aikibudo. In 1942, it was renamed as Aikido.