With the formation of the Ōuetsu Reppan Dōmei of northern domains against the imperial government, Tendō initially attempted to remain neutral, but joined the alliance in September 1868.
Tendō's actions were influenced by the creation of the Ōuetsu Reppan Dōmei, an alliance opposing the imperial government. Initially trying to remain neutral, he eventually joined the alliance in September 1868.