Historically, the relationship between the emperor and the crown prince, the relationship between the emperor and the emperor, called father and son, was actually a political enemy and was often in the middle of a game. This layer of window paper is well known to everyone, but in the era of filial piety, in order to maintain the harmony of the father-son relationship on the surface, everyone will not easily break it.
If the emperor suddenly dies, the emperor and the crown prince exist at the same time, and theoretically the prince should succeed to the throne, the main reason:
First, the crown prince is the crown prince of the country, and the legitimacy of succession is the strongest.
In ancient times, in the agricultural civilization of the Central Plains, the inheritance system was generally the succession of fathers and sons. What is a prince? It is the successor designated by the Son of Heaven. When the emperor reigned, he created a prince for his own sake, and he could be smoothly continued by the prince after a hundred years. This system is both a ritual and a practice.
The Emperor Taishang was generally in a state of retirement, more of an honor in status, and lacked a legal basis for restoration.
Second, people's hearts are turned back.
Ancient Chinese public opinion was controlled by Confucian intellectuals, a group of staunch defenders and trumpeters of traditional rituals. In their view, there was already a stipulation in the Zhou Li that it was a matter of course for the father to die and the son to succeed and the prince to ascend to the throne, and whoever went against the heavens was a sinner for eternity.
Especially before the Qing Dynasty, many Confucian intellectuals in China had the feeling of "to the emperor Yao Shun, and then make the customs pure", seeing the Taishang Emperor grabbing the crown prince's throne, some people will stand up, even if they sacrifice their lives for righteousness, they will also argue on the basis of reason and defend the etiquette.
However, at the practical level of operation, whether it is the Emperor Taishang or the Crown Prince, who has great ambitions, strong strength, and hard fists can achieve his wishes.
History has shown that the throne is not stable. This instability will reach its peak when there is a power vacuum when the emperor dies, and at this time, the imperial power struggle, all feelings, benevolence and righteousness are floating clouds, and strength is the king.
If the prince is a soft persimmon, and the emperor is strong and wants to be the emperor, then there is a high probability that he will be restored. For example, Qianlong, if Jiaqing takes the first step after he ascends the throne, he is afraid that the old master will be "forced" to pay because of the support of the courtiers.
Historically, there were originally very few people who became emperors, except for Qianlong, the rest of the people often had a more sad ending. For example, Li Yuan and Li Longji, when Empress Taishang became a toothless tiger, mentally no different from the prisoners, without any strength to reset.
The only time the "Emperor Taishang" who was not emperor Taishang was restored was still Emperor Mingyingzong Zhu Qizhen.
Zhu Qizhen was the eighth emperor of the Ming Dynasty and was captured by the Mongols during the "Tumu Fort Revolution". When the emperor was captured in the grasslands, the chancellor of the court was anxious, and the country could not be without a monarch for a day, so the ministers headed by Yu Qian supported Zhu Qiyu, the king of Qi, as emperor.
After Zhu Qiyu became emperor, Yaozun's captured brother Zhu Qizhen became emperor taishang, and at the same time, he vigorously resisted the Mongols and refused the Mongols' conditions for Zhu Qizhen to be used as a bargaining chip. The Mongols could not defeat the Ming Dynasty, and had no choice but to retreat to the steppe.
Later, the Mongols had the sincerity to negotiate peace, and found that Zhuqi Town could not become a valuable chip, and it was better to raise it in vain every day, but it was better to be a Shunshui person and put it back to Daming.
After returning to The Town of Zhu Qi, he was immediately placed under house arrest, but the imperial court still had a group of forces to support him. After being placed under house arrest for seven years, the "hardcore" of Zhu Qizhen took advantage of Zhu Qiyu's serious illness to launch a "change of seizing the door" and quickly supported the "Emperor Taishang" Zhu Qizhen to restore the throne.
The issue of the transfer of imperial power, from the beginning of Qin Shi Huang, has always plagued the emperors of successive dynasties. This is not only the emperor's family affair, but also related to the foundation of the dynasty, solved can reduce the cost of handover, and if it is not solved well, it will shake the mountain, and even leave endless hidden dangers for future generations.