In the Otate Disturbance, Kagekatsu occupied the donjon and treasure-house of Kasugayama Castle immediately after Kenshin's death on the false premise that it was bequeathed to him by Kenshin, and then he fought against Kagetora, who holed up in Otate (the residence of Norimasa UESUGI) located outside the walls of Kasugayama Castle.
御館の乱において、景勝は謙信の死の直後に謙信の遺言と詐称して春日山城本丸と金蔵を占拠し、春日山城城下の御館（上杉憲政の屋敷）に立て籠もった景虎と戦った。