Buddhism Zen Buddhism is divided into two main schools: Rinzai (臨済宗) and Sōtō (曹洞宗), the former greatly favouring the use in meditation on the koan (公案, a meditative riddle or puzzle) as a device for spiritual break-through, and the latter (while certainly employing koans) focusing more on "shikantaza" or "just sitting". Zen Buddhism is primarily found in Japan, with some presence in South Korea and Vietnam. The scholars of Japanese Soto Zen tradition in recent times have critiqued the mainstream Japanese Buddhism for "dhatu-vada", that is assuming things have substantiality, a view they assert to be non-Buddhist and "out of tune
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