Pianhai states it is pronounced gua (level tone). Its pronunciation is the same as the character pronounced guo (rising tone). It means to stop up the mouth, as cited in the Suzi Beipian. Furthermore, Zihui Bu states it is pronounced ying (rising tone). Its pronunciation is the same as the character pronounced ying (level tone). In the collections of the Three Academies of the Song Dynasty, there is a work titled San ma sou in three volumes, which contains accounts regarding the rearing of eagles and hawks.