- Other name: Kamiizumi Nobutsuna
Kamiizumi Hidetsuna learned Aisu-Kage Ryu from Aisu Hisatada, and founded Shin-Kage Ryu. He declined a personal offer by Takeda Shingen to join the Takeda clan as a vassal, however he did accept the character "Nobu" (From Shingen's name Harunobu).
- Nihon Densho Bugei Ryuha Dokuhon(日本伝承武芸流派読本) Shinjinbutsu Orai sha 1994
- Biography of Takeda Shingen