Frank E. Reynolds, Ph.D., Professor of History of Religions and Buddhist Studies, University of Chicago: The original home of Zen Buddhism was India, but it was not until it was carried to China, then to Korea and Japan, that it reached its fullest potential.
The essence of Zen is that all beings are already enlightened. They simply do not know it yet. The goal of Zen, therefore, is to awaken people to their own spiritual nature and this is accomplished through meditation.
source: no. 1, pp. 72-75
The goal of Zen is the attainment of a state of spiritual enlightenment called satori. Zen Buddhists believe meditation is the key to achieving satori. There are two major schools of Zen, Rinzai and Soto. Followers of Rinzai meditate on the meaning of baffling riddles called koans while sitting cross-legged. People who practice Soto meditate in the same position. They also read from the sacred works of Mahayana Buddhism, another East Asian form of the religion. Zen Buddhists believe physical labor contributes to the attainment of enlightenment. They work closely with a teacher called the master, who guides their search for satori.
Zen developed in China, where it is called Chan. According to legend, an Indian monk named Bodhidharma first taught its principles in China in the A.D. 500’s. Two Japanese priests, Eisai and Dogen, introduced Chan into Japan. Eisai founded the Rinzai school in the 1100’s, and Dogen established the Soto school in the 1200’s. Zen Buddhism is practiced primarily in Japan and has greatly influenced Japanese culture.