Zen Buddhism is not a theory, an idea, or a piece of knowledge. It is not a belief, dogma, or religion; but rather, it is a practical experience. We cannot intellectually grasp Zen because human intelligence and wisdom are too limited - the dojo (the hall where Zazen is practiced) is different from the university.
Zen is not a moral teaching, and as it is without dogma, it does not require one to believe in anything. A true spiritual path does not tell people what to believe in; rather it shows them how to think; or, in the case of Zen - what not to think.
Zen is not a theory, an idea, or a piece of knowledge. It is not a belief, a dogma, or a religion...Zen Buddhism is not interested in metaphysical theories and rituals and focuses entirely on the mindful practice of Zazen. Zen is very simple. It is so simple, in fact, that it's very difficult to grasp.
In the silence of the dojo or temple, quietly sit down, stop moving, and let go your thoughts. Focus just on your Zazen posture and your breathing. Keep your back straight. Let your ego and your unconscious mind melt away, merge with the universe. This is Zen.
from and for Michael Dickes