Around this time, infighting began between the group aiming to install Joan NAITO as a lord of the castle and the group backing the birth child of Kunisada NAITO, Senshomaru (later known as Sadakatsu NAITO).
このころより内藤ジョアンこそ城主とすべき派と、内藤国貞の実子、千勝丸（後の内藤貞勝）の擁立を目指す一派とで内争となった。