The period after the death of the Buddha is sometimes divided into three ages: in the Age of the True Dharma (the first ten-century period), the Buddha’s teaching is practiced and enlightenment can be attained; in the Age of the Semblance Dharma (the second ten-century period), the teaching is practiced but enlightenment is not possible; in the last period of 10,000 years (the Latter Age of Degeneration), the teaching exists but it is no longer practiced.

(Note 8, Writings of Nichiren Shōnin, Doctrine 1, Page 143)