Since his original name was Genji (Minamoto clan), his official name was MINAMOTO no Yoshitsune, which was an identical name with the famous MINAMOTO no Yoshitsune from the Kawachi-Genji (Minamoto clan) as a brother of MINAMOTO no Yoritomo, so he was known in the 'Two Yoshitsune Theory.'
本姓が源氏であるため正式な姓名は源義経であり、源頼朝の弟として有名な河内源氏の源義経と同姓同名であったため「義経二人説」で知られる。