The Soka Gakkai is an organization of a new religious movement which is founded on Buddhism. It was established by Tsunesaburo Makiguchi (1871-1944) and Jogai (later Josei) Toda (1900-1958) in 1930. Makiguchi and Toda interpreted Buddhism so as to be well suited to modern times. Therefore the Soka Gakkai is also based on their interpretations of Buddhism. And now the Soka Gakkai has been propagated worldwide by the leadership of Daisaku Ikeda.
    A main creed of the Soka Gakkai is that the Lotus Sutra is the supreme Buddhist scripture of all. The Lotus Sutra was created in Mahayana Buddhism, which tried to interpret Buddhism differently from Hiinayana Buddhism for salvation of all sentient beings.
    In the 13th century a priest Nichiren (1222-1282) in Japan, for the first time, interpreted the Lotus Sutra to be well suited to the Latter Day of the Law (mappo), and he established the Three Great Secret Laws which were, he argued, the only way to attain Buddhahood in the Latter Day. The Soka Gakkai believes that Nichiren's interpretations of the Lotus Sutra were valid on the whole. Furthermore Nichiren thought that a Buddha was a person who attained Buddhahood, namely, the highest state of life, or the noblest character. And lastly he emphasized social responsibility of religion in Rissho ankoku ron (On Establishing the Correct Teaching for the Peace of the Land).
    In early Showa era Makiguchi and Toda found out the significance of Nichiren's interpretations of Buddhism (Nichiren's Buddhism) and they established the Soka Kyoiku Gakkai (Value-Creating Education Society, the former organization of the Soka Gakkai) in 1930, so they started a new religious movement. In this paper I would like to describe Nichiren's interpretations of the Lotus Sutra in the first part. And I would like to describe how Makiguchi and Toda accepted and interpreted the Lotus Sutra and Nichiren's Buddhism, which lays the foundation of some religious ideas of the Soka Gakkai.