Mastery of ju or "giving way" is not so simple as it sounds. It is the result of sincere effort. The device of giving way until the proper time involves the use of perfect balance, rhythm and harmony, and perception--the kinesthetic or "sixth-sense" feel--of the opponent's
off-balance movements. It is this that enables the judoist to gain eventual victory. When his opponent attacks, he must harmonize his own movements with the opponent's brute force in order to gain victory. Thus his preliminary retreat is performed with the goal of ultimate victory in mind.
Watanabe and Avakian