Su Zhipo: a famous musician and pipa player from Northern Zhou Dynasty to Sui Dynasty. Su Zhipo once learned the theory of seven modes, such as "Five Dan" and "Seven Tones" used in the Western Regions from his father, and he brought this theory to the Central Plains. At that time, Zheng Yi, a musician, learned the theory of Qiuci Pipa and Qiuci Music from Su Zhipo and founded the theory of 84 Tones. Su's musical tune system laid the theoretical foundation of the famous 28 tunes of Yan music in Tang Dynasty, which was an important turning point in the history of ancient Chinese music development and made outstanding contributions to the development of Chinese national musical law. Therefore, the pipa flourished and became the main national musical instrument in China.