Nichiren was a Buddhist monk who lived during the Kamakura period in Japan. Nichiren taught devotion to the Lotus Sutra, entitled Myouhou-Renge-Kyou in Japanese, as the exclusive means to attain enlightenment and the chanting of Nam-Myouhou-Renge-Kyou as the essential practice of the teaching. Various schools with diverging interpretations of Nichiren's teachings comprise Nichiren Buddhism.
Nichiren was born on February 16, 1222 in the village of Kominato, Nagase District, Awa Province (within present-day Chiba Prefecture). Nichiren's father was Mikuni-no-Tayu Shigetada, also known as Nukina Shigetada Jiro and his mother was Umegiku-nyo. On his birth, his parents named him Zennichimaro (善日麿) which has variously been translated into English as "Splendid Sun" and "Virtuous Sun Boy" among others. The exact site of Nichiren's birth is believed to be submerged off the shore from present-day Kominato-zan Tanjo-ji, a temple in Kominato that commemorates Nichiren's birth.
Some traditions suggest that Nichiren's family was associated with the Fujiwara clan. However, Nichiren never made such a claim and historians are skeptical of its accuracy. Nichiren wrote that he was "the son of a chandala family who lived near the sea in Tojo in Awa Province, in the remote countryside of the eastern part of Japan." This has been interpreted to mean that Nichiren's family made their living in the fish trade, an occupation viewed with disdain by idealistic Buddhists of the time. Another suggestion is that Mikuni-no-Tayu Shigetada, Nichiren's father, had been a samurai, but had grown disillusioned with violence and retired to Kominato to make a living as a fisherman. Nichiren makes no such claim in his authenticated writings.
Nichiren began his Buddhist study at a nearby temple of the Tendai school, Seicho-ji, at age 11. He was formally ordained at 16 and took the Buddhist name Zeshou-bou Renchou. He left Seicho-ji shortly thereafter to study in Kamakura and several years later traveled to western Japan for more in-depth study in the Kyoto–Nara area, where Japan's major centers of Buddhist learning were located. During this time, he became convinced of the pre-eminence of the Lotus Sutra and in 1253, returned to Seichoji.
On April 28, 1253, he expounded Nam Myouhou Renge Kyou for the first time, marking his Sho Tem Pou Rin (初転法輪: "first turning the wheel of the Law"). With this, he proclaimed that devotion and practice based on the Lotus Sutra was the correct form of Buddhism for the current time. At the same time he changed his name to Nichiren, nichi (日) meaning "sun" and ren (蓮) meaning "lotus". This choice, as Nichiren himself explained, was rooted in passages from the Lotus Sutra.
After making his declaration, which all schools of Nichiren Buddhism regard as marking their foundation, Nichiren began propagating his teachings in Kamakura, then Japan's de facto capitol since it was where the shikken (regent for the shogun) and shogun lived and the government was established. He gained a fairly large following there, consisting of both priests and laity. Many of his lay believers came from among the samurai class.