The third son, Sadakuni UTSUNOMIYA, joined the Southern Court of Imperial Prince Kagenaga in Kyushu, joining his elder brother Sadahisa, and died fighting in the Battle of the Chikugo-gawa River with his nephew, Kanehisa UTSUNOMIYA.
三男の宇都宮貞邦は、兄貞久と共に懐良親王の九州の南朝方となり、甥の宇都宮懐久と共に筑後川の戦いで討ち死する。