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
Buddhism in Vietnam and a new Thiền style has "no affinity with or any foundation in traditional Vietnamese Buddhist practices" and according to Alexander Soucy (2007) his style of Zen Buddhism is not reflective of actual Vietnamese Buddhism. Thích Nhất Hạnh often recounts about his early Thiền practices in Vietnam in his Dharma talks saying that he continued and developed this practice in the West which has a distinctive Vietnamese Thiền flavor. Thích Nhất Hạnh's Buddhist teachings have started to return to a Vietnam where the Buddhist landscape is now being shaped by the combined Vietnamese and Westernized Buddhism that is focused more