Nichiren Buddhists interpret the prophecy of three time periods to justify that their teaching is a proper practice for the last period of the Law:
"Three periods ［三時］ ( san-ji): (1) The Former Day, Middle Day, and Latter Day of the Law. Three consecutive periods or stages into which the time following a Buddha’s death is divided. These are also referred to as the periods of the Correct Law, the Counterfeit Law, and the Decadent Law (or the Final Law). During the Former Day of the Law, the spirit of Buddhism prevails, and people can attain enlightenment through its practice. During the Middle Day of the Law, although Buddhism becomes firmly established in society, it grows increasingly formalized, and fewer people benefit from it. In the Latter Day of the Law, people are tainted by the three poisons of greed, anger, and foolishness, and lose their aspiration for enlightenment; Buddhism itself loses the power to lead them to Buddhahood. There are several explanations of the lengths of the three periods following the death of Shakyamuni Buddha. One describes the Former Day and the Middle Day as each lasting one thousand years, and another, five hundred years. A third account has the Former Day lasting for one thousand years, and the Middle Day for five hundred years; and a fourth states that the Former Day lasts for five hundred years, and the Middle Day for one thousand years. All accounts agree that the Latter Day will continue for ten thousand years. In China, Shakyamuni Buddha’s death was placed in the fifty-second year of the reign of King Mu (949 b.c.e.) of the Chou dynasty, and the period of the Former Day was defined as five hundred years and that of the Middle Day as one thousand years. Accordingly, it was believed that the Latter Day had begun in the mid-sixth century. In Japan, Shakyamuni Buddha’s death was placed in the same year as in China, but an account that defines each period of the Former Day and the Middle Day as one thousand years was accepted, and it was believed that the Latter Day had begun in 1052. Usually these three periods refer to the time after Shakyamuni Buddha’s death, but they also pertain to other Buddhas who appear in the sutras. For example, according to the Lotus Sutra, Bodhisattva Never Disparaging lived toward the end of the Middle Day of the Law of the Buddha Awesome Sound King. See also Former Day of the Law; Latter Day of the Law; Middle Day of the Law.
(2) A reference to the teachings of the three periods. See three periods, teachings of the."