The Tsu family was a declining noble house related to the Igi clan in Miyama Province in Kozakura in 1357 DR.
They still controlled the kokushu position but little more than that. In the past, the Igi were considered vassals of the Tsu but around 1357 DR, the Igi dominated the Tsu.
- ↑ David Cook (1986). Swords of the Daimyo (Province Book of Miyama). (TSR, Inc), pp. 11–12. ISBN 0-88038-273-2.