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
Buddhism in Vietnam (, "Collection of Outstanding Figures of the Zen Garden") has been the dominant text used to legitimize Thiền lineages and history within Vietnam. However, Cuong Tu Nguyen's "Zen in Medieval Vietnam: A Study and Translation of the Thien Tap Anh" (1997) gives a critical review of how the text has been used to create a history of Zen Buddhism that is "fraught with discontinuity". Modern Buddhist practices are not reflective of a Thiền past; in Vietnam, common practices are more focused on ritual and devotion than the Thiền focus on meditation. Nonetheless, Vietnam is seeing a steady growth in Zen