The Sekihō Army was an anti-bakufu militia comprised of farmers and merchants that arose after the Battle of Toba-Fushimi in 1868, during the closing days of the Bakumatsu. Commanded by Sagara Sōzō, the Sekihō Army was split into units in order to better fulfill its missions and was sent as an advance team for the Ishin Shishi forces, collecting intelligence on each area and recruiting soldiers against the bakufu.
At the behest of the new revolutionary government, the Sekihō Army spread news of the impending tax reforms that would effectively cut all taxes in half. Though this news did manage to bring several domains over to the new government's side, rising expenditures during the war left the politicians in a vulnerable position, as they would be unable to follow through with their promise. Hoping to save face, the Meiji Government sent word around the country that labelled the Sekihō Army as frauds and slandered them as liars. An order went out from the Ishin Shishi commanding general to every unit of the regular forces that the members of the Sekihō Army were to be captured or eliminated as punishment for raising people's hopes with "falsified reports of a tax reform".
A unit of the Sekihō Army stationed at Usui cliff was attacked and decimated by revolutionary forces and, upon hearing word of this new turn of events, Sagara Sōzō and his men of the first unit traveled from their position in the eastern mountains to military headquarters in Shimosuwa in the hopes of reaching a compromise and sparing his men. instead, however, Sagara's unit was attacked and defeated at Shimosuwa and Sagara himself was executed by decapitation. Up until their executions, all captured members of the Sekihō Army were forced to wear prison clothes with the kanji character aku (惡) - meaning evil - emblazoned on their backs.