"Tiangu" is a saying in physiognomy. In the Southern Tang and Song Dynasties, Qiu Qi's "Jade Tube Shines on God" said: "The forehead has heavenly bones, and the eyes have luminous eyes, which are called Ruxiang. However, there is no consistent view on the morphological characteristics of different phases in each phase book. In addition to the facial characteristics, it generally involves the content of sound phase and line equality.