Aikido is a martial art of Japanese origin that was developed by Morihei Ueshiba otherwise known as "O'Sensei". It is founded upon the principle of using the attacker's own power and momentum against the attacker. With that same principle it can be practiced regardless of a person's size, weight and strength.
Aikido's practice is derived from the old samurai arts thus the Aikidoka will be training not only with hand to hand techniques but also with weapons such as the sword, long staff and knife/dagger.