Zen is Chinese before it is Japanese, and Indian before that
The word travelled from Sanskrit dhyāna, meditative absorption, to Chinese chan to Japanese zen. The school itself formed in Tang-dynasty China by fusing Indian Mahayana philosophy with Taoist thought. Only in 2018 did Merriam-Webster add lowercase zen, meaning simply calm, a long way from its monastic roots.
Chan began as the meditation school, also called the Buddha-mind school, and tradition credits its arrival in China to Bodhidharma, a semi-legendary monk from India or Central Asia. From China it spread in three directions: south to Vietnam as Thiền, northeast to Korea as Seon, and east to Japan as Zen. Its philosophy draws on Indian Yogacara and Madhyamaka ideas blended with Neo-Daoist thinking.
Zen stresses sitting meditation, zazen in Japanese, and direct insight into one's own Buddha nature, known as kenshō, expressed through everyday life for others' benefit. Some Zen writings downplay scripture in favour of practice and encounters with a master, sometimes portrayed as an unconventional rule-breaker. In reality most Zen schools still keep chanting, precepts, walking meditation, ritual, monastic life and textual study.
Its intellectual sources are wide: early Sarvāstivāda meditation, bodhisattva teachings, the Laṅkāvatāra and other Tathāgatagarbha texts, and the Huayan school. The Prajñāpāramitā literature and Madhyamaka thought help explain the paradoxical, negating style of Zen talk. The phrase Buddha-mind can mean either an enlightened Buddha's compassion or the originally pure mind present in every being, waiting to be awakened.
Meditation reached China much earlier than the school. Translators An Shigao, active around 148 to 180 CE, and Kumārajīva, who lived from 334 to 413, rendered dhyāna sutras based largely on Kashmiri Sarvāstivāda teaching. These texts taught five methods, among them mindfulness of breathing and loving-kindness, which modern Chan master Sheng-yen called ways of pacifying the mind. Their influence lasted: the 18th-century Rinzai master Tōrei Enji wrote a commentary on one of them and believed Bodhidharma had written it.
Source: Zen
