Zen is a school of Mahayana Buddhism that originated in China during the Tang dynasty as the Chan School or the Buddha-mind school, and later developed into various sub-schools and branches. It is characterized by the practice of dhyana or meditation, especially sitting meditation, which is known as zazen in Japanese. Zen is the direct experience of what is called ultimate reality or the absolute, yet it is not separate from the ordinary, the relative. It is both something we are—our true nature expressing itself moment by moment—and something we do—a disciplined practice through which we can realize the joy of being. Zen is not a belief system to which one converts, and there is no dogma or doctrine associated with it. It is a state of calm attentiveness in which one's actions are guided by intuition rather than by conscious effort