According to legend, Yoichi pardoned his older brothers who were on the run in Shinano and other areas and allotted land to them, and he constructed a foundation for the development of the Nasu clan in Shimotsuke Province.
与一は信濃など各地に逃亡していた兄達を赦免し領土を分け与え、下野国における那須氏発展の基礎を築いたとされる。