Kunichiyo (国千代, Kunichiyo) is the third of Ieyasu's grandsons. Though younger, it's clear he inherited his grandfather's intelligence and cunning over his elder brother, Takechiyo. For this reason many officials wihin the Shogunate believe he should succeed his father as Shogun, forming a faction lead by his mother Oeyo. He is represented by Kouga Manjidani. As an adult he is renamed Tadanaga Tokugawa. It is unknown of his fate when his brother successed their father as the next Shogunate
Often called Suruga Dainagon (the major counsellor of Suruga), Tadanaga was born in 1606. His birth name was Kunichiyo. The date of his birth is uncertain, and is variously given as May 7, June 1, and December 3. Blessed with military and intellectual prowess and a generosity of spirit, he received support from his mother, Oeyo (or Sūgen'in), who favored him over her other son Takechiyo (the future Iemitsu) to become the third shogun. Just before the death of their father shogun Hidetada, Iemitsu accused his brother, already under house arrest in Kofu, of insanity, stripped him of all possessions and offices, leaving him to commit seppuku.