Imperial Prince Tadafusa (忠房親王)

Imperial Prince Tadafusa (1285? - around August, 1347) was a member of the Imperial Family in the Kamakura period. His father was MINAMOTO no Hikohito, the grandchild of Emperor Juntoku, and his mother was the daughter of Morotada NIJO, a Juichii Kanpaku (Junior First Rank, chief adviser to the Emperor). Although Tadafusa's grandfather, Iwakuranomiya Prince Tadanari (the fifth prince of Emperor Juntoku), was regarded as the most likely candidate for succession to the Imperial Throne after the death of Emperor Shijo, he was defeated in the race to decide the next heir due to obstruction by the Kamakura bakufu (Japanese feudal government headed by a shogun) and was instead granted the reigning name of Iwakuranomiya. Like Tadafusa's father Hikohito, the Imperial Prince used the family name of Minamoto until he was given the title of Imperial Prince, so he was also called MINAMOTO no Tadafusa. He married a daughter of Kanemoto NIJO, the Juichii Kanpaku. He had a prince, MINAMOTO no Hikoyoshi, but another theory suggests that Prince Yotsutsujinomiya Songa and his son, MINAMOTO no Yoshinari, were actually the princes of Imperial Prince Tadafusa. His siblings were Imperial Prince Shochinho, Imperial Princess Moriko, and Genkaku.

Favored by Emperor Gouda, the Imperial Prince was adopted by the Emperor and promoted to the Gon Chunagon (Provisional Middle Counselor). Subsequently, he was given the title of Imperial Prince and in the latest issue on deciding the successor of the Imperial Throne in the Heisei period, this has been valued as a precedent by the group supporting the resurrection of the former Imperial Family, as it meant a commoner had entered the Imperial Family.

The word Yushi (猶子, the adopted child) means to treat like an Imperial Prince and it is believed to have been put into practice in the Imperial Family for the first time when "Shokugensho" (a book on Japanese government officials) asserted that Imperial Prince Tadafusa was the Yushi of Goudain (the Retired Emperor Gouda). However, the word Yushi is one of Chinese origin, and referred in "Raiki" (book on rites).