It is said that Kanto-Shichiryu was established by seven Shinto priest families from Katori-jingu Shrine and Kashima-jingu Shrine to whom the art of kenjutsu had been passed on by Futsunushi no kami and Takemikazuki when these kami settled in Katori county and Kashima county (Ibaragi Prefecture) after the conquest of Ashihara no nakatsukuni due to the tenson korin (descent of the grandson of the sun goddess).
関東七流は、日本神話で葦原中国平定を成功させた経津主神とタケミカヅチが香取郡鹿島郡(茨城県)地方に居ついて以降、天孫降臨より香取神宮・鹿島神宮の神職に伝承され、その7家から発すると云われる。