Originally a Japanese branch of Mahayana Buddhism. It teaches a doctrineless path to enlightenment, based upon existentialism and intuition. Transcendence acquired in Zen is the only state of being that validates self.
Calvin Miller, Transcendental Hesitation, [Out of print] Zondervan Corporation, 1977, p.175
Chinese CH'AN (from Sanskrit dhyana, "meditation"), important school of Buddhism in Japan that claims to transmit the spirit or essence of Buddhism, which consists in experiencing the enlightenment (bodhi) achieved by Gautama the Buddha.
Zen teaches that the Buddha-nature, or potential to achieve enlightenment, is inherent in everyone but lies dormant because of ignorance. It is best awakened not by the study of scriptures, the practice of good deeds, rites and ceremonies, or worship of images but by a sudden breaking through of the boundaries of common, everyday, logical thought. Training in the methods leading to such an enlightenment (Chinese wu; Japanese Satori,) is best transmitted personally from master to disciple. The methods recommended, however, differ among the various sects of Zen.
Zen, Encyclopedia Britannica
Zen Buddhists seeks salvation by experiencing satori, which is the Japanese term for enlightenment.
Buddhism, Taoism, & Other Far Eastern Religions J. Isamu Yamamoto, Zondervan, Grand Rapids, MI, 1998. p.50
Perhaps no Eastern religion is considered more chic and intellectually sophisticated in America today than Zen Buddhism. Offering an autonomous path to mystical enlightenment that does not demand acceptance of Eastern mythology and culture, Zen is well suited for the ''post-modern'' American. Yet, J. Isamu Yamamoto maintains, Zen is actually an anti-intellectual approach to truth that denies fundamental human needs
Zen (Neutral) Entry in Encyclopedia Britannica
International Research Center for Zen Buddhism Japanese academic research institution at Hanazono University, devoted to the study of Zen Buddhism.