Dhyāna in Buddhism "silent illumination." This became the source of some differences in practice between the Línjì and Cáodòng schools. A kōan, literally "public case", is a story or dialogue, describing an interaction between a Zen master and a student. These anecdotes give a demonstration of the master's insight. Koans emphasize the non-conceptional insight that the Buddhist teachings are pointing to. Koans can be used to provoke the "great doubt", and test a student's progress in Zen practice. Kōan-inquiry may be practiced during zazen (sitting meditation), kinhin (walking meditation), and throughout all the activities of daily life. Kōan practice is particularly emphasized by
Zen in the United States "Chán"), Korean Zen (or "Seon"), and Vietnamese Zen (or "Thien"). The first Chinese Buddhist monk to teach Westerners in America was Hsuan Hua, a disciple of the 20th-century Chan master, Hsu Yun. In 1962, Hsuan Hua moved to San Francisco's Chinatown, where, in addition to Zen, he taught Chinese Pure Land, Tiantai, Vinaya, and Vajrayana Buddhism. Initially, his students were mostly ethnic Chinese, but he eventually attracted a range of followers. In 1970, Hsuan Hua founded Gold Mountain Monastery in San Francisco and in 1976 he established a retreat center, the City Of Ten Thousand Buddhas, on a 237-acre (959,000