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.

Link to relevant part of the Gosho.

Part 1

Part 2

Part 3: This episode

An introduction to Nichiren Daishonin's Buddhism.

https://www.nichirenlibrary.org/en/wnd-1/Introduction/3#The%20Life%20of%20Nichiren%20Daishonin:~:text=peacefully%20passed%20away.-,Nichiren%20Daishonin%E2%80%99s%20Buddhism,-Nichiren%20Daishonin%E2%80%99s%20Buddhism

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

A brief biography of Nichiren Daishonin, the Buddha of the Latter Day of The Law.

https://www.nichirenlibrary.org/en/wnd-1/Introduction/3#The%20Life%20of%20Nichiren%20Daishonin:~:text=of%20its%20inhabitants.-,The%20Life%20of%20Nichiren%20Daishonin,-Nichiren%20Daishonin%20was

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.

https://www.nichirenlibrary.org/en/wnd-1/Content/2

This letter was written at Minobu in the eighth month of the first year of Kenji (1275) to the lay nun Myōshin, a believer who lived in Nishiyama in Fuji District of Suruga Province. It explains that the Gohonzon is “the essence of the Lotus Sutra and the eye of all the scriptures.” The Gohonzon, or mandala, embodies the reality of the three thousand realms in a single moment of life implicit in the “Life Span” chapter of the Lotus Sutra. Thus, the Gohonzon is the “essence of the Lotus Sutra.” And the Lotus Sutra is the eye of all the teachings of Shakyamuni. Therefore, the Gohonzon, the “essence of the Lotus Sutra,” is also the “eye of all the scriptures.”

https://www.nichirenlibrary.org/en/wnd-1/Content/73

Nichiren Daishonin wrote this letter to Sairen-bō Nichijō while at Ichinosawa on Sado Island in the fifth month of the tenth year of Bun’ei (1273). For some reason Sairen-bō was also in exile on Sado, where he had been converted by the Daishonin in the second month of 1272. A former Tendai priest, he already knew something about “the true aspect of all phenomena”; it was a fundamental concept in the Tendai school of Buddhism. He could not, however, satisfactorily come to grips with this concept through T’ien-t’ai’s theory alone, so he asked the Daishonin for an explanation. The True Aspect of All Phenomena is the Daishonin’s reply.

Though comparatively short, this document elucidates two important elements of the Daishonin’s Buddhism. It was completed a month after Nichiren Daishonin wrote The Object of Devotion for Observing the Mind, in which he explained the Gohonzon, the object of devotion that can lead all people in the Latter Day of the Law to enlightenment. True Aspect of All Phenomena begins with a passage from the “Expedient Means” chapter—the heart of the theoretical teaching of the Lotus Sutra—that implies that no phenomenon is in any way different from the true aspect, or Myoho-renge-kyo. It also implies that all the innumerable forms and realities that exist, both concrete and abstract, are manifestations of Myoho-renge-kyo. The Daishoninthen explains the essence of the Lotus Sutra, Myoho-renge-kyo, and its embodiment, the Gohonzon. This is the first element—the object of devotion in terms of the Law.

After clarifying the ultimate teaching of the Lotus Sutra, the Daishoninstates that Bodhisattva Superior Practices, the leader of the Bodhisattvas of the Earth, will propagate that teaching, and that he himself is carrying out the mission entrusted to that bodhisattva. In light of his own behavior and his fulfillment of the predictions in the Lotus Sutra, Nichiren Daishonin suggests that he himself is Bodhisattva Superior Practices. A more profound interpretation, however, identifies him as the Buddha of the Latter Day of the Law, whose purpose was to establish the Gohonzon for the enlightenment of all people in the Latter Day. Thus True Aspect of All Phenomena also explains the object of devotion in terms of the Person. This is the second element. Referring to both the Person and the Law, the Daishonin clarifies the fundamental object of devotion for the people of the Latter Day. He brings together the points he expounded in The Opening of the Eyes completed in 1272, which focuses on the second element, and in The Object of Devotion for Observing the Mind, which focuses on the first element.

The latter half of this letter explains to Sairen-bō that those who devote themselves to propagating the correct teaching in the same spirit as the Daishonin are themselves Bodhisattvas of the Earth. The Daishonin predicts that Nam-myoho-renge-kyo will spread widely in the future, and concludes by setting forth the key elements of Buddhist practice in the Latter Day of the Law—namely, faith, practice, and study.

https://www.nichirenlibrary.org/en/wnd-1/Content/40

This letter was written to Hyōe no Sakan Munenaga, the younger of the two Ikegami brothers. Though it was originally thought to have been written in the first year of Kenji (1275), it is now apparent that it was written in 1277. Munenaga is thought to have taken faith in the Daishonin’s teaching around 1256, shortly after his elder brother Munenaka. Both were officials in the Kamakura shogunate, and their father, Yasumitsu, was director of the government’s Office of Construction and Repairs.

Yasumitsu was a loyal follower of the priest Ryōkan of the True Word Precepts school who was highly active in political affairs. He strenuously opposed their beliefs and disowned Munenaka twice, in 1275 and again in 1277. By disowning Munenaka, Yasumitsu in effect was provoking a rift between the two sons, tempting the weaker Munenaga to trade his beliefs for the right to inherit his father’s estate. Supported by the Daishonin’s guidance and encouragement, however, Munenaga upheld his faith together with his brother, and in 1278, after a total of twenty-two years’ practice, their united efforts finally led their father to accept faith in the Daishonin’s teaching.

https://www.nichirenlibrary.org/en/wnd-1/Content/77

This letter was written at Minobu in the eleventh month of the third year of Kōan (1280) in response to a petition from the lay nun Nichigon. She is thought to have been either a relative of the lay priest Takahashi, a central figure among the believers in Fuji District of Suruga Province, or the mother of Nichigen, a priest of Jissō-ji temple in the same province who converted to Nichiren Daishonin’s teachings.

https://www.nichirenlibrary.org/en/wnd-1/Content/155?cmdf=reply+to+lay+nun+nichigon

On the ninth day of the tenth month, 1271, on the eve of his departure for Sado Island, Nichiren Daishonin wrote this letter to Chikugo-bō Nichirō, who was later to become one of his six senior disciples. Nichirō and his father had converted to the Daishonin’s teachings in 1254, and Nichirō had received the tonsure under the supervision of his uncle Nisshō, also later to become one of the six senior disciples. At the time of the Tatsunokuchi Persecution in the ninth month of 1271, Nichirō and several other priest-disciples were imprisoned in the custody of Yadoya Mitsunori, an official of the Kamakura government, in a dungeon carved into the side of a hill near Mitsunori’s residence in Kamakura. 

In the interval between the Tatsunokuchi Persecution and his exile to Sado Island, the Daishonin was held at the mainland residence of Homma Rokurō Saemon, the deputy constable of Sado, in Echi of Sagami Province. It was here that the Daishonin wrote this letter, which demonstrates that, even when about to embark for a destination sure to be marked by privation and hardship, his chief concern was for his disciples.

https://www.nichirenlibrary.org/en/wnd-1/Content/26