1 year has been lost, such as the history before Shang Dynasty. Because of the long history, there is no clear written record, so it can only be taught orally, without the assistance of words, and its reliability is greatly reduced.

For example, every time a dynasty changes, most new monarchs will tamper with the history of the previous dynasty and beautify their political achievements, so as to play a political role and influence people's thoughts.

3 Deliberately concealing, most rulers will conceal some unfavorable events, such as countless unsolved cases in history: axe sound and candle shadow, three cases in the late Ming Dynasty ... These cases are generally kept in unofficial history, but their authenticity has been difficult to verify and become unsolved.

The subjective influence of historians, such as the most famous History of the Three Kingdoms, obviously has the idea of respecting Liu and restraining Cao, which is influenced by both feudal orthodoxy and historians' subjectivity.

But generally speaking, China is one of the countries with the most complete civilization in history, and its historical credibility can be said to be the highest.