The Ōuetsu Reppan Dōmei (奥羽越列藩同盟, lit. 'Alliance of the domains of Mutsu, Dewa, and Echigo') was a Japanese military-political coalition established and disestablished over the course of several months in early to mid-1868 during the Boshin War. Its flag was either a white interwoven five-pointed star on a black field, or a black interwoven five-pointed star on a white field. It is also known as the Northern Alliance (北部同盟, Hokubu Dōmei).