On the twenty-eighth day of the fourth month, 1253, Nichiren Daishonin established the teaching of Nam-myoho-renge-kyo at Seichō-ji temple in his native province of Awa, and later he returned to Kamakura, the seat of the military government, to begin propagation. In examining the records, we find that in those days the era names were changed frequently. The year 1253 was in the Kenchō era. Three years later, in 1256, the era name changed to Kōgen, and the next year, to Shōka. Then, two years later, in 1259, it was changed to Shōgen, the following year to Bunnō, and the year after that to Kōchō. In the five years from 1256 to 1261, the era name changed five times. An era name was usually changed only on the accession of a new emperor, or when some natural disaster of severe proportions occurred; the frequency of these changes attests to the magnitude of the disasters that struck Japan during this period.

Soon after the Daishonin’s arrival, Kamakura and the country as a whole faced a series of disasters and conflicts that served to emphasize his conviction that the Latter Day of the Law had indeed been entered upon. On the sixth day of the eighth month of 1256, torrential rainstorms caused floods and landslides, destroying crops and devastating much of Kamakura. In the ninth month of the same year, an epidemic swept through the city, taking many lives. During the fifth, eighth, and eleventh months of 1257, violent earthquakes rocked the city, and the sixth and seventh months witnessed a disastrous drought. Most frightful of all was an earthquake of unprecedented scale that occurred on the twenty-third day of the eighth month. The year 1258 witnessed no lessening of natural calamities. The eighth month saw storms destroy crops throughout the nation, and floods in Kamakura drowned numerous people. In the tenth month of the same year, Kamakura was visited by heavy rains and severe floods. In the first month of 1258, fires consumed Jufuku-ji temple, and in 1259, epidemics and famine were rampant, and a violent rainstorm decimated crops.

Link to relevant part of the Gosho.

Part 1

Part 2: This episode