Killed February 14, 940, in Shimosa Province by the allied forces of Fujiwara no Hidesato and Taira no Sadamori. He had proclaimed himself "New Emperor" and established an independent regime in the Kanto region, but was suppressed within two months. Legend says his severed head, displayed in Kyoto, opened its eyes after three days and flew eastward seeking its body. This mound marks where it fell. Attempts to move or demolish the site have allegedly triggered curses—incidents were reported after the Great Kanto Earthquake and when GHQ planned its removal.