Due to his rigorous scholarship, Sima Qian studied many documents and materials since the Yellow Emperor, but because of the ambiguous and inconsistent years, he abandoned them. He believes that only from the Republic can credibility be higher. As you said, his previous records are basically untraceable, of course, he has similar records later. For example, Liu Xin wrote in the Annals of the Han Dynasty: "The first year of the Han Dynasty was too early, ten years before the Shang Dynasty." "I was 132 and 113 years old when I was in the Yuan Dynasty, and I was in charge of Jiazi House in 88, and I was 127 years old after I entered Jie." , "Shang Yuan reached the year of cutting the week, 142, 19 years old", so Liu Xin speculated that the week was cut in 1 122 BC. (143127-142109+104 =1122) His basis is three links, four points, Li Yin and Chunqiuli. Besides, there are many unscientific settings in Shangyuan, which are generally not accepted. Besides, what Sima Qian saw was gone when he arrived in Liu Xin. Therefore, the history of faith began in the first year of the Republic recorded in historical records.