One of the most important scholars of Zen Buddhism, Daisetz Suzuki, cogently explained the origins of Zen Buddhism in 1959:
Zen is one of the products of the Chinese mind after its contact with Indian thought, which was introduced into China in the first century C.E. through the medium of Buddhist teachings. There were some aspects of Buddhism in the form in which it came to China that the people of the Middle Kingdom did not quite cherish: for instance, its advocacy of a homeless life, its transcendentalism or world-fleeing and life-denying tendency, and so on. At the same time, its profound philosophy, its subtle dialectics and penetrating analyses and speculations, stirred Chinese thinkers, especially Taoists. (p. 3)
For several centuries in China, it was thought that Buddhism was a form of Daoism returning from India along the Silk Roads. Bernard Faure relates: "At the end of his life Laozi, in the guise of the Buddha, was said to have departed to the west to convert the barbarians. To punish them for their initial lack of faith, he condemned them to celibacy" (p. 39). Conversely, the Buddhists claimed that Laozi and Confucius were sent to China to pave the way for Buddhism. In any event, many forms of Buddhism arrived in China from India.
Between the sixth and tenth centuries, Buddhism reached its apex in China with the appearance of four schools: Tiantai (Celestial Platform), Huayan (Flower Garland), Jingtu (Pure Land), and Chan (Meditation). The Sanskrit word dhyana is transcribed as Chan in Chinese and Zen in Japanese, meaning "collectiveness of mind or meditative absorption in which all dualistic distinctions like I/you, subject/object, and true/false are eliminated" (Schuhmacher and Woerner, p. 441). Chan is a melding of Dhyana Buddhism with its emphasis on the stillness of meditation toward enlightenment or awakening (wu, satori) and Daoism with its emphasis on nonaction (wuwei) as the way of the water. Bodhidharma (470–543), the twenty-eighth patriarch after Shakyamuni Buddha, arrived from India at the Shaolin temple in China, where he practiced seated meditation (zuochan, zazen) for nine years in front of a wall. This meditation aimed to clear the mind of daily desires while allowing the sitter to connect his or her true nature with the universe through the achieving of śūnyata (kong, ku, emptiness). Ninian Smart states that Bodhidharma, the first patriarch, is reputed to have summarized his teaching as follows: "A special transmission outside the scriptures; No basis in words or writing; Direct pointing to the mind of people; Insight into one's nature and attainment of Buddhahood" (p. 126).
The sixth patriarch, Huineng (638–713), refined Bodhidharma's teachings by emphasizing master-student relationships in monasteries and meditation upon what later would become "public documents" (gongan, koan) or unsolvable riddles. One day Huineng encountered two monks arguing about a flag waving in the breeze. One monk said that the flag was inanimate and that only the wind made it flutter. The other monk said there was no flapping at all because only the wind moved. Huineng intervened. He said that neither the flag nor the wind moved, only their minds.
Huineng debated with Shenxiu (606–706) regarding immediate or gradual enlightenment. He relates:
"Good friends, in the Dharma there is no sudden or gradual, but among people some are keen and others dull. The deluded commend the gradual method; the enlightened practice the sudden teaching. To understand the original mind of yourself is to see into your own original nature. Once enlightened, there is from the outset no distinction between these two methods; those who are not enlightened will for long kalpas be caught in the cycle of transmigration" (Yampolsky, p. 137).
Shenxiu's northern school of gradual enlightenment soon gave way to Huineng's southern school of immediate enlightenment. Willard Oxtoby observes that Huineng's school "became known for freedom of expression and respect for the natural. Similar characteristics are associated with Daoism" (p. 270). At this time, China was ripe for Chan Buddhism. Kenneth Ch'en writes: "For over one hundred and thirty years, from 625 to 755, the T'ang Dynasty had enjoyed tranquility, security, and prosperity without any internal rebellion or external invasion to mar the orderly march of events. During this era all phases of Chinese culture, religion, art, and literature enjoyed a long period of free growth and development" (p. 360).
In the ninth century, the Caodong zong (Caodong school) and Linji zong (Linji school) sects of Chan Buddhism carried on the rivalry of gradual and sudden enlightenment. Caodong favored gradual, silent enlightenment through seated meditation. The gradual stillness of mind is like "the bird hatching the egg" (Oxtoby, p. 272). Linji favored immediate awakening through the practice of shouting, beating, and paradoxical sayings that were later compiled as gongan. Unanticipated shouting and blows between master and pupil could result in enlightenment. Similarly, reflection on riddles could end in a sudden awakening, like "the blossoming of a lotus or the sun emerging from behind the clouds" (Oxtoby, p. 272). The Linji master might answer a student's query "Who is the Buddha?" with the quip "three pounds of flax." Alternatively, the master might propose the riddle "What is the sound of one hand clapping?" The purpose was to encourage the student to abandon all logic and reasoning while searching for peace in the quietude of meditation.
During the Southern Song dynasty of the twelfth century, the interaction of Chinese and Japanese monks stimulated the migration to Japan of Linji (Rinzai Zen) and Caodong (Soto Zen). Eisai (1141–1215) brought Rinzai and Dogen (1200–1253) brought Soto. The Kamakura period (1185–1333) was a watershed for Zen Buddhism. Rinzai's emphasis on the controlled discipline of seated meditation and the contemplation of koan became popular among the ruling samurai clans at Kamakura. Soto's more exclusive focus on seated meditation appealed to the peasantry. Zen's influence in the arts included painting, literature, and calligraphy and carried on well into the modern era. Zen and the sword, Zen and archery, Zen and tea were intimately connected to samurai culture.
The juxtaposition of Zen's humanity and samurai warfare is difficult for Westerners to understand. At Shaolin, the Chan monks practiced martial arts (gongfu) to keep themselves physically fit while defeating their worst enemy: their own desire. In a world of suffering, desire is the root of misery. To do away with desire is to clear a way to the "extinction" of suffering (nirvana). In Japan the samurai were intimately linked to Zen. If Buddhism is the pure negation of the will as the extinguishing of desire, then Bushido (the warrior's way) is the pure will as the negation of the negation or the annihilation of nirvana. The juxtaposition of Zen and the warrior spirit is the essence of samurai culture. This alluring paradox is one reason that Suzuki's style of Rinzai Zen became popular in the Western world after World War II.