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
Doctrinal background of Zen Doctrinal background of Zen Zen has a rich doctrinal background, despite the traditional Zen narrative which states that it is a "special transmission outside scriptures" which "did not stand upon words." Classical Chinese Chán is characterised by a set of polarities: absolute-relative, Buddha-nature - sunyata, sudden and gradual enlightenment, esoteric and exoteric transmission. The Prajnaparamita-sutras and Madhyamaka emphasized the non-duality of form and emptiness: "form is emptiness, emptiness is form", as the heart sutra says. This was understood to mean that ultimate reality is not a transcendental realm, but equal to the daily world of relative reality. This idea fitted