Buddha-Dharma and the Middle Path
Buddhism, or Buddha-Dharma, is a result of the quest undertaken by the Śākya prince, Siddhārtha Gautama, to understand the human condition and his role within it. Western societies widely regard Buddhism as a religion and while this is true to some extent Buddhism is also a way of life.
Established around 500 BC, Buddhism has branched out over time with many different schools and branches, the main two of which are Mahāyāna and Theravāda.
Nichiren Diashonin
Nichiren Diashonin was a 13th Century Japanese monk. He believed that the Lotus Sutra, which was the Buddha's final lecture, to be his most supreme teaching and the pinnacle that his followers should aspire to. Thus Nichiren taught that if one was to recite the title of the Lotus Sutra, known as the daimoku, then one could attain the Truth of the world that the Buddha had known. Nichiren's ideas about the nature of the Buddha's teaching was considered radical during his lifetime. As a result Nichiren was subject to multiple arrests, exiles and orders of execution by the Japanese government. Despite the attempts to silence him, Nichiren was able to establish a devoted following and taught 6 principle disciples.
Following Nichiren's death, his disciples established several schools of "Nichiren Buddhism" based upon their interpretations of his teachings and writings. It is from these schools of Nichiren that the modern Nichiren schools we know today have evolved, the largest of which are Nichiren Shōshū and Nichiren Shū. Additional lay groups have also developed over the years. The largest of these lay groups in the Soka Gakkai International or SGI. SGI has a rather large following globally with its highest membership occuring before it formally split from Nichiren Shōshū in the 1990s.
References
Daniel A. Métraux, "The Dispute between the Sōka Gakkai and the Nichiren Shōshū Priesthood: A Lay Revolution against a Conservative Clergy." Japanese Journal of Religious Studies Vol. 19, No. 4 (Dec., 1992), pp. 325-336
Hideo Hashimoto and William McPherson, "Rise and Decline of Sokagakkai Japan and the United States." Review of Religious Research Vol. 17, No. 2 (Winter, 1976), pp. 82-92
Jacqueline I. Stone, "Review: Biographical Studies of Nichiren." Japanese Journal of Religious Studies Vol. 26, No. 3/4, Revisiting Nichiren (Fall, 1999), pp. 441-458
Nichiren. The Writings of Nichiren Shōnin. Complied by Kyōtsū Hori, Jay Sakashita. Tokyo: Shunjū-sha, 1994.