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
Dhyāna in Buddhism Zen, but makes Zen practice also vulnerable to misunderstanding and exploitation. B. Alan Wallace holds that modern Tibetan Buddhism lacks emphasis on achieving levels of concentration higher than access concentration. According to Wallace, one possible explanation for this situation is that virtually all Tibetan Buddhist meditators seek to become enlightened through the use of tantric practices. These require the presence of sense desire and passion in one's consciousness, but "jhāna" effectively inhibits these phenomena. While few Tibetan Buddhists, either inside or outside Tibet, devote themselves to the practice of concentration, Tibetan Buddhist literature does provide extensive instructions on it, and