In late Edo period, local feudal lords were commanded by the Shogun to guard the Imperial Palace. The Choshu clan (based in current Yamaguchi Prefecture) had a duty to guard this Gate. Because the Choshu clan, which were very conservative at the time, were supporting the anti-foreigner policies and gaining power within the court, court nobles and clans against Choshu tried to displace their power. On August 18, 1863, troops including the Satsuma clan (based in current Kagoshima Prefecture) took over Sakaimachi Gate and literally shut the Choshu out of Kyoto for a time. This battle mainly took place right here.