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 Japan began teaching devotion to the "Lotus Sutra". Eventually, his disciples formed their own school of Nichiren Buddhism, which includes various sects that have their own interpretations of Nichiren's teachings. Nichiren Buddhism established the foundation of Japanese Buddhism in the thirteenth century. The school is known for its sociopolitical activism and looks to reform society through faith. In the Muromachi period, Zen, particularly the Rinzai school, obtained the help of the Ashikaga shogunate and the Emperor of Japan, and accomplished considerable development. After the Sengoku period of war, Japan was re-united in the Azuchi–Momoyama period. This decreased the power of Buddhism,