Nichiren Shū (日蓮宗, Nichiren-shū, Nichiren School) is a confederation of four of the original Nichiren Buddhist Schools that date back to Nichiren's original disciples, and part of the fifth:
The school's Head Temple, Kuon-ji, is located on Mount Minobu where Nichiren lived in seclusion and where he asked to be buried. Another important temple of Nichiren Shū is Ikegami Honmon-ji where Nichiren died. Its temples have many of Nichiren’s most important personal artifacts and writings (which are considered National Treasures of Japan) in their safekeeping.
Nichiren Shū does not believe Nichiren designated a single successor, as taught for instance by Nichiren Shoshu, but that he designated Six Senior Disciples to succeed him. The Six Senior Disciples designated by Nichiren were: Nissho (1221-1323); Nichiro (1245-1320); Nikko (1246-1333); Nikō (1253-1314); Nitchō (1252-1317); and Nichiji (1250-unknown).
Nichiren (日蓮; February 16, 1222– November 21, 1282) was a Buddhist monk who lived during the Kamakura period (1185–1333) in Japan. Nichiren taught devotion to the Lotus Sutra, which claims to contain Gautama Buddha's teachings towards the end of his life, as the exclusive means to attain enlightenment. Nichiren believed that this sutra contained the essence of all of Gautama Buddha's teachings related to the laws of causality, karma, and leading all people without distinction to enlightenment. This devotion to the sutra entails the chanting of Namu Myōhō Renge Kyō "homage to the Lotus Sutra", a phrase referred to as the daimoku, as the essential practice of the teaching.
Nichiren Buddhism includes various schools such as Honmon Butsuryū Shū, Nichiren Shōshū, the Nichiren Shū confederation of schools, and lay movements such as Risshō Kōsei Kai or Soka Gakkai, each claiming to be the only true follower of their founder, with their own interpretations of Nichiren's teachings. However, despite the differences between schools, all Nichiren sects share the fundamental practice of chanting daimoku. While all Nichiren Buddhist schools regard him as a reincarnation of the Lotus Sutra's Visistacaritra or Jōgyō Bosatsu (上行菩薩), some schools of Nichiren Buddhism's Nikkō lineages regard him as the actual Buddha of this age, or the Buddha of the Latter day of the Law and for all eternity.