The standing Zen used to gain an understanding of ki is performed only by martial arts men and is different from the seated Zen meditation of Zen Buddhism, the ultimate goal of which is psychological discipline.  Of course, in standing Zen too psychological discipline is important, for the person must be able to react in a mindless way to the opponent's moves and must not rely on conscious judgments.  But the standing meditation regimen has physical aspects as well.  These are related to the physical training of the martial arts and are based on the premise that instantaneous motion must be possible at all times. (There is a modification of full standing Zen that is called half-Zen or han-Zen).

It is best to practice standing Zen in the morning and out of doors.  New spiritual powers only well up in human minds when people are in a natural setting.  Furthermore, each person must be entirely flexible in his attitude toward place and conditions of training.  That is to say, each person must be able to train anywhere and at any time.  The idea that training halls, training equipment and opponents are requirements of training may express interest in the martial arts but does not reveal the attitude of a person truly devoted to them.  Standing Zen among the trees gives one an indescribably good feeling of being in harmony with nature.  Ki is born of this kind of Zen even when the person is temporarily out of sorts or not in the mood for what he is doing.