The Soka Gakkai Dictionary of Buddhism
Former Day of the Law[正法] (Jpn shobo )
Also, age of the Correct Law or age of the True Dharma. The first of three periods following Shakyamuni's death. In this age, the teaching, practice, and proof of Shakyamuni's teachings are all present, and those who practice Buddhism and attain enlightenment are more numerous than in the ages that follow. According to The Annotations on "The Treatise on the Middle Way" and other works, the Former Day of the Law of Shakyamuni Buddha lasts for one thousand years, though other sources state its length as five hundred. The Great Collection Sutra defines the first five hundred years of the Former Day of the Law as the "age of attaining liberation," in which many people are sure to attain emancipation through practicing the Buddha's teachings. It defines the second five hundred years as the "age of meditation," in which meditation will be widely practiced. See also three periods.