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
History of Buddhism may have arrived as early as the 3rd or 2nd century BCE via India, or alternatively during the 1st or 2nd century from China. Whatever the case, Mahayana Buddhism had been established by the second century CE in Vietnam. By the 9th century, both Pure Land and Thien (Zen) were major Vietnamese Buddhist schools. In the southern Kingdom of Champa, Hinduism, Theravada and Mahayana were all practiced until the 15th century, when an invasion from the north led to the dominance of Chinese-based forms of Buddhism. However Theravada Buddhism continues to exist in the south of Vietnam. Vietnamese Buddhism is