In the Senji—shō Nichiren reviewed the history of the spread of Buddhism after the Parinirvāṇa of the Buddha, and reaffirmed once again his often repeated conviction that the Age of the Last Law was the most significant period since the death of the Buddha for the propagation of the Lotus Sūtra. Since his age (Age of the Last Law) was the fifth of the five five hundred year periods, Nichiren thought a conflict would take place between the True Buddhism and what he called heretical Buddhism. He stated in the Senji—shō that the persecutions he suffered and the national calamities which the nation experienced were indications of the crisis when the decision between the truth and falsehood, between the one who was a messenger for the Buddha (himself) and his opponents must be decided. In other words, Nichiren saw the crisis facing Japan as the period just prior to the establishment of the True Buddhism, which would flourish during the Age of the Last Law.

Nichiren looked back in the Senji-shō at the persecutions he had to suffer over the years, and examined the prediction he made in order to demonstrate that he had been given the sacred mission, as the messenger of the Buddha, to establish Japan as the center from which the true Buddhism would spread throughout the world.