The Japanese word Aikido is written with three characters which translate as "the way of unity with the fundamental force of the universe".

Aikido is a true budo or Martial Way that evolved in the historic tradition of Japanese warrior arts. Studied in earnest, budo is more than a science of tactics and self-defense - it is a discipline for perfecting the spirit.

Aikido was developed by Morihei Ueshiba, known as O-Sensei (Great Teacher) to more than one million students of Aikido throughout the world. Even as a young man, he was an extraordinary martial artist, a master of the sword, the staff, the spear, and the art of ju-jitsu. But O-Sensei also had a strong spiritual drive, and brooded over the futility of a path based on victory over others.

Leading a life of austerity and rigorous training, he struggled with this dilemma. It was resolved in a moment of profound awakening. Transformed by his spiritual insights, Ueshiba's technical mastery evolved into a martial art of refinement and astonishing power, fundamentally different from those that preceded it.

"The secret of Aikido," he wrote, "is to harmonize with the movement of the universe and bring ourselves into accord with the universe itself." O-Sensei maintained that budo is a work of love, a path to overcome discord in ourselves and bring peace to the world, "to make the heart of the universe one's own heart."

There have always been visionaries of remarkable insight, but O-Sensei taught that true awareness is not grasped by intellect alone. "This is not mere theory," he said. "You must practice it."

Quotes by Morihei Ueshiba (from The Art of Peace)

Morihei Ueshiba biography information (from The Art of Peace)

The essence of all Aikido techniques is spherical motion around a stable, energized center. Even when the direction appears to be straight forward or backward, close observation reveals the Aikidoist's movements are in fact circular.

Properly executed, some techniques are spectacular, sending an opponent flying through the air. Others are like sleight-of-hand: small, deft movements that immobilize the aggressor. Both results are achieved through precise use of leverage, inertia, gravity, and the action of centrifugal and centripetal forces. Ultimately, it is the energy of the attack itself which brings down the attacker.

Increased stamina, flexibility, and muscle development occur naturally as a result of training, but the techniques themselves do not depend on strength for effectiveness; Aikido can be practiced by men and women of all ages.

The final aim of budo is personal transformation, the creation of an integrated human being. Yet philosophical discussion is rare in the dojo, or training hall. The focus is highly practical: constant repetition to master the fundamentals of movement, timing and breathing.

Students train themselves to capture the opponent's action and redirect it with techniques of martial efficiency and power. At the same time, they become aware of the tendency to overreact to opposition, and learn to remain centered under all conditions.

Most practice is done with a partner; each works at his or her own level of ability, alternating as uke (the attacker), and nage (the one who receives the attack). Both roles are stressed: each contributes skills that enhance overall sensitivity and control.

The Aikidoist acquires a relaxed posture in which the weight of the body is directed towards its physiologic center in the lower abdomen. Gravity, no longer a force to be overcome, serves to support and stabilize posture. As a result, ordinary movement assumes an appearance of grace and economy.

The effects of centering are mental as well as physical: vitality increases, the senses are sharpened, and one is less affected by everyday irritations and annoyances. This state is referred to in Japan as having hara, or strong ki, the inner quality which aids the student of Aikido to develop to his or her fullest potential in every area of life.

( This information is originally from the USAF Website )