In the age of 'Gen Pei To Kitsu,' when a strong Shizoku family like the Minamoto clan, the Taira clan, or the Fujiwara or Tachibana clans, were in their prime, a part of the Shizoku population that moved to local regions began to use other names, for example like a place name, for its Kamei (Yago, house name) to distinguish themselves from other people from the same clan, and this led to Myoji (family name) being used later.
「源平藤橘（げんぺいとうきつ）」と呼ばれる源氏、平氏、藤原氏、橘氏といった強力な氏族が最も名を馳せていた時代、地方に移り住んだ氏族の一部が他の同じ氏族の人間と区別をはかるため土地の名前などを自分の家名（屋号）とし、それが後の名字となった。