- Other name: Seishichirô
Hidetsuna at first held Tochio castle in Echigo province. Hidetsuna was active in Kenshin's campaigns in the Kanto and defended Numata castle in 1573. He supported Uesugi Kagetora in the Ôtate no Ran in 1578 and was later forced to flee to Aizu by Uesugi Kagekatsu.
- Initial text from Samurai-Archives.com FWSeal & CEWest, 2005