Nichiren (日蓮) (February 16, 1222 – October 13, 1282) was a Buddhist monk who lived during the Kamakura period (1185–1333) in Japan. Nichiren taught devotion to the Lotus Sutra (entitled Myōhō-Renge-Kyō in Japanese)— which contained Gautama Buddha's teachings towards the end of his life — as the exclusive means to attain enlightenment. Nichiren believed that the sutra contained the essence of all of Gautama Buddha's teachings, of which related to the law of cause and effect and karma. This devotion to the sutra entails the chanting of Nam(u)-Myōhō-Renge-Kyō (referred to as "daimoku") as the essential practice of the teaching.
Nichiren Buddhism includes various schools with their own interpretations of Nichiren's teachings, the most prominent being Nichiren Shu, Nichiren Shoshu and Soka Gakkai; however, despite the differences between schools, all Nichiren sects share the fundamental practice of chanting daimoku. While virtually all Nichiren Buddhist schools regard him as a reincarnation of the Lotus Sutra's Bodhisattva Superior Practices, 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.
Read more about Nichiren: Life, Nichiren’s Identity and Posthumous Titles, Development of Nichiren's Teachings, Writings