Zen is a school of Mahayana Buddhism that originated in China during the Tang dynasty, known as the Chan School, and later developed into various sub-schools and branches. From China, Chán spread south to Vietnam and became Vietnamese Thiền, northeast to Korea to become Seon Buddhism, and east to Japan, becoming Japanese Zen. The term Zen is derived from the Japanese pronunciation of the Middle Chinese word 禪 (chán), an abbreviation of 禪那 (chánnà), which is a Chinese transliteration of the Sanskrit word ध्यान dhyāna ('meditation'). Zen emphasizes rigorous self-restraint, meditation-practice and the subsequent insight into nature of mind (見性, Ch. jiànxìng, Jp. kensho, 'perceiving the true nature') and nature of things (without arrogance or egotism), and the personal expression of this insight in daily life, especially for the benefit of others. As such, it de-emphasizes knowledge alone of sutras and doctrine, and favors direct understanding through spiritual practice and interaction with an accomplished teacher or Master.

Zen - Wikipedia