Two Reasons of Nichiren's Choice of the Lotus Sutra

After Nichiren took tonsure and became a priest, he studied Buddhism hard. Soon he had a question as follows. "Though there are many sects of Buddhism, what was the final intention of the Buddha Shakyamuni?" And he followed the saying in the Nirvaa.na Sutra that one should rely on the Law (sutras) and not upon persons (priests). So he was engaged in comparative studies of many sutras, and he came to the conclusion that the Lotus Sutra is the supreme sutra of all. [1]
    There are, Nichiren thought, two reasons why the Lotus Sutra is the supreme sutra of all. First, according to T'ien T'ai's doctrine of the five periods and eight teachings, the Lotus Sutra is the sutra which shows the final intention of the Buddha Shakyamuni. In the Immeasurable Meanings Sutra (Muryogi kyo), [2] a passage tells that all other sutras which have been taught before it, are not the final sutra and that they are inferior to it. And in the introduction of the Lotus Sutra, there is a suggestion that the Immeasurable Meanings Sutra was taught before the Lotus Sutra (L.S., p.5). And in Nirvaa.na Sutra, which was taught last by the Buddha Shakyamuni, there is a suggestion that the Lotus Sutra is superior to the Nirvaa.na Sutra (On Repaying Debts of Gratitude, W.N.D., p. 692). So Nichiren concluded that the Lotus Sutra is the supreme sutra of all.
    Secondly as for salvation of all sentient beings, in the Lotus Sutra there are two teachings which have not been taught in any other sutras. The first teaching is that persons of the two vehicles (Hiinayaanists) will be able to attain Buddhahood. These two kinds of persons can't attain Buddhahood in other Mahaayaana sutras. And the second teaching is that the Buddha Shakyamuni attained Buddhahood in reality at an inconceivable distant time in the past and has been saving sentient beings since then. So the Buddha Shakyamuni who was born in India was merely a provisional manifestation of that eternal Buddha Shakyamuni. Nichiren thought that the Lotus Sutra tells that the eternal Buddha and his first disciples, Bodhisattvas who rise up out of the ground, will save all sentient beings in the Latter Day of the Law when other sutras can't save. So the Lotus Sutra, Nichiren believed firmly, is the supreme sutra of all especially in the Latter Day of the Law.