Nichiren trained as a young monk on Mount Hiei, the center of Tendai Buddhism, where Chinese Tiantai scholarship, especially the systematic ranking of the Buddha's teachings associated with the patriarch Zhiyi, had long held the Lotus Sutra as the culmination of the Buddha's forty-nine years of preaching, the sutra in which he set aside provisional teachings suited to his listeners' capacities and taught the single buddha vehicle directly. Nichiren radicalized that ranking into an exclusive claim: in the present age of mappo, the degenerate final era of the Dharma, only the Lotus Sutra's own practice, not its philosophical study, could actually save people, and that practice was the daimoku, the chanted invocation of the sutra's title, Nam-Myoho-Renge-Kyo, offered before a mandala inscription, the gohonzon, that Nichiren himself designed to represent the sutra's central assembly.
Nichiren announced this teaching publicly, by his own account, at Seicho-ji temple in 1253, and pressed it for the rest of his life in increasingly confrontational terms, submitting a treatise to the Kamakura shogunate in 1260, the Rissho Ankoku Ron, arguing that Japan's earthquakes, famine and threat of Mongol invasion were consequences of the country's devotion to what he judged false teachings, chiefly Pure Land nembutsu practice and Zen. The treatise led to exile, an attempted execution and repeated persecution, which Nichiren read as confirmation of the Lotus Sutra's own prediction that its true votary would suffer for the teaching's sake.