1. In the ancient Zhou Dynasty, Su Fensheng was a Zhou Wuwang sheep herder, and his grandson took the official name as his surname, and it was said that his surname was Kou; 2. In the ancient Spring and Autumn Period, Wei Kangshu was Zhou Sikou, and his grandson took the official as his surname, and some said that his surname was Kou; 3. Xianbei nationality evolved from Xianbei nationality, with an accent surname, and the word "kou" with similar pronunciation was adopted as the surname after the sinicization.