Aikido originated from Aiki jujutsu, founded by Minamoto Yoshimitsu in the twelfth century. The aikido as we know it today was developed by Ueshiba Morihei in the 1920's. This form of martial arts emphasizes self defense and is often considered to be a spiritual exercise. Aikido methods include throws and holding techniques solely to protect oneself from attack, and methods to seek weaknesses in the wrist and arm joints of opponents. Aikido has no offensive techniques, and therefore, the sport does not hold competitive tournaments. Today, there are about 500 aikido dojo (facilities), and about a million participants world wide.