Under the
Muromachi shogunate, the Uesugi clan was appointed to the post of
Kantō Kanrei, but through continuous warfare their situation was greatly weakened. In 1507,
Nagao Tamekage of the Fuchū-Nagao cadet branch of the clan overthrew his Uesugi overlords. On his death in 1543, his son
Nagao Harukage was unable to hold the clan together, and turned authority over to his brother, Kagetora, later known as
Uesugi Kenshin. However, the Ueda-Nagao under
Nagao Masakage initially opposed Kenshin and raised an army. He was defeated, but was allowed to pledge
fealty to Kenshin, and was married to Kenshin's younger sister, Sento-in, after which the Ueda-Nagao clan contributed to Kenshin's campaigns against the
Takeda clan and the
Odawara Hōjō clan. In 1564, Masakage died in what may have been an accident, and his son, Akikage was adopted by Kenshin, becoming
Uesugi Kagekatsu. Kenshin's sudden death in 1578 without having named an heir set the stage for another major conflict, the
Siege of Otate, as Kenshin's other adopted son,
Uesugi Kagetora also claimed the position of heir. Kagekatsu was supported by Kenshin's closest guards and quickly captured
Kasugayama Castle and the Ueda-Nagao rallied to his banner. However, Kagetora had the support of the most important retainers as well as backing by the Takeda and Hōjō clans, and isolated Kasugayama Castle from the Uonuma basin. In the summer of 1578, the Hōjō invaded Echigo in support of Kagetora while the Takeda invaded from Shinano Province. Unable to fight a war on two fronts, Kagekatsu quickly made a separate peace with the Takeda; however, the Hojo were able to lay siege to many of the border castles in the Uonuma region, including Sakado. The defenders were fortunate in that the Hōjō laid siege after the rice harvest had been competed. Furthermore, as the Uonuma area is a region of Japan with the heaviest snowfalls, the Hōjō armies suffered greatly once winter began, and as the snow began to disrupt their supply lines, they were forced to retreat. Kagekatsu was thus able to counterattack and reestablish the link between Kasugayama Castle and his main power base at Sakado. The following spring, in March 1579, Kagekatsu made a major offensive against Kagetora, taking his headquarters at Ōtate Castle. Kagetora fled to
Samegao Castle, where he was betrayed and committed suicide. Uesugi Kagekatsu was thus master of Echigo and undisputed head of the Uesugi clan, but the conflict had left the Uesugi clan greatly weakened, and he was forced to submit fealty to
Toyotomi Hideyoshi. Sakado Castle continued to be used as a border fortification for Echigo. In 1598, the clan was transferred to
Aizu on the orders of Hideyoshi and the province was given to
Hori Hideharu. Hideharu placed
Hori Naoyori as castellan of Sakado Castle. Naoyori made many modifications to the castle and the hillside residence. In 1608, he was transfer to become
daimyō of
Iida Domain in
Shinano Province by the
Tokugawa shogunate and Sakado Castle was abandoned. ==Current==