Take the early Western Han Dynasty as an example: the rulers in the early Han Dynasty not only saw the advantages of Qin's unification and the establishment of centralization of authority, but also adopted the ruling measures of "Han inherited the Qin system". We can also see that the Qin dynasty did not change its ruling strategy because of the passage of time, and it was too "promising", which led to the people's hardship, boiling resentment and the demise of tyranny. The policy of "being with the people" and "quietism" has brought about political stability, economic recovery and development. Accordingly, we should face history correctly, respect it, not be confused by its glory, nor be depressed by its decline, learn from it and turn it into valuable wealth.

In other words, Emperor Taizong and Li Shimin adjusted their ruling policies (specifically) on the basis of summing up the experience and lessons of their predecessors (Sui Dynasty), and the rule of Zhenguan appeared during their reign.