This letter was written at Minobu in the eleventh month of the fourth year of Kōan (1281) to the lay nun Ueno, the mother of Nanjō Tokimitsu. The Daishonin was sixty years old when he sent this letter acknowledging the offerings she had made to commemorate the anniversary of the death of her father, the lay priest Matsuno Rokurō Saemon.

The lay nun Ueno’s husband was Nanjō Hyōe Shichirō, the steward of Ueno Village in Suruga Province. Her name, Ueno, derived from Ueno Village. She had nine children, including Tokimitsu.

In this letter, the Daishonin first teaches that, just as the lotus bears flowers and fruit simultaneously, all who believe in the Lotus Sutra are certain to attain Buddhahood. Then, citing the story of the renowned father and son calligraphers in ancient China, Wu-lung and I-lung, the Daishoninassures the lay nun that, when a son or daughter embraces faith in the Lotus Sutra, his or her parents will be able to attain Buddhahood. According to the story, though Wu-lung fell into the state of hell for his hatred of the Lotus Sutra, he was ultimately saved from his suffering by his son’s transcribing the titles of the eight volumes of the sutra. This story is found in The Lotus Sutra and Its Traditions, a work by the T’ang-dynasty priest Seng-hsiang.

https://www.nichirenlibrary.org/en/wnd-1/Content/162