A DAUGHTER opens up the gate of another household, a son carries on the house in which he was born. Though one may be the ruler of the whole country of Japan, if he lacks a son, who will succeed him? Though he may have riches enough to fill a major world system, if he lacks a son, to whom can he bequeath them?
Therefore the three thousand and more works of non-Buddhist literature call someone who has a son a rich man, and the five thousand and more works of the Buddhist canon speak of someone with no son as a poor man. A son and a daughter are like the sun and moon in the sky, the directions east and west on the earth, the two wings of a bird, or the two wheels of a carriage.
Therefore I ask that you call this son of yours Hiwaka Gozen.1 I will write in more detail at another time.
The twenty-sixth day of the eighth month in the third year of Kōan 
Reply to Ueno
Addressed to Nanjō Tokimitsu, the steward of Ueno Village, Suruga Province, this letter was written at Minobu in 1280. In it, Nichiren Daishonin congratulates Tokimitsu on the birth of a son, for whom he proposes the name Hiwaka Gozen. The Daishonin points out, according to the custom of his time, that while a daughter leads another household to prosper, a son becomes heir where he was born. Comparing a son and daughter to the sun and moon, he suggests that children are irreplaceable treasures.
1. Probably the eldest son of Nanjō Tokimitsu. Hi, of Hiwaka, means sun, and waka means young or a little child; Gozen is an honorific title.