Looking at the feudal imperial succession system for more than two thousand years (excluding the founding emperor), the general principle followed is the inheritance of the eldest son, specifically, there is a concubine, no concubine, the father dies and the son succeeds, the brother dies and the brother dies. In the emperor's view, only his own sons could inherit the throne.
However, we find such a phenomenon that Zhao Kuangyin, the founding emperor of the Northern Song Dynasty, obviously had four sons, the eldest son Zhao Dexiu the Prince of Teng, the second son Zhao Dezhao the King of Yan, the third son, Zhao Delin the Prince of Shu, and the fourth son, Zhao Defang, the King of Qin. Since both Zhao Dexiu and Zhao Delin died early, Zhao Dezhao was the eldest son and Zhao Defang was the second son.
In terms of inheritance principle, Zhao Dezhao should be the first heir to the throne. In the second year of Qiande (964 AD), the 13-year-old Zhao Dezhao left the cabinet. According to the custom, the crown prince was to be crowned king when he left the cabinet, but Zhao Kuangyin, because Zhao Dezhao was young, did not grant the title of king. Until Zhao Kuangyin died violently, Zhao Dezhao was unable to be crowned king.
Looking at Zhao Dezhao's resume, at the time of Zhao Kuangyin's death, his title was Xingyuan Yinshan Nanxi Dao JieduShi Tong Zhongshu Menxia Pingzhangshi, one step away from being crowned king. Because of this, soon after Zhao Guangyi took the throne, he made Zhao Dezhao the King of Wugong County. Back to the previous topic, why didn't Zhao Kuangyin make the 25-year-old Zhao Dezhao the crown prince before he died?
It should be noted here that the "axe sound of candle shadow" has been controversial for thousands of years and will not be discussed here. The reason why Zhao Kuangyin did not make Zhao Dezhao crown prince is closely related to the rules of the five dynasties to the early Northern Song Dynasty. At that time, Tianzi's qi was exuberant, and the so-called "Tianzi Ning has a kind of Yay? Soldiers are strong and strong! In layman's terms, it was an era of "power out of the barrel of a gun", and whoever had the biggest fist could be king.
Zhao Kuangyin was added to his body through the yellow robe of the "Chen Qiao Mutiny", and he was well aware of the importance of military power. When Zhao Kuangyin first ascended the throne, his sons were not adults, and there were still a large number of enemies outside the Northern Song Dynasty, such as the Later Han and Southern Tang, and even the inside of the Northern Song Dynasty was unstable, "After Taizu took the throne, the car first came out, crossed the Daxi Bridge, flew arrows and shot yellow umbrellas, and the guards were horrified." The emperor draped his chest and smiled: "Teach shooting and teach shooting." 'Even if you are still inside, you will try to catch the thief, but the emperor will not listen, and for a long time, there will be nothing to do.' ”
In this case, does Zhao Kuangyin dare to set up a son? Obviously not. Zhao Kuangyin was able to establish the Northern Song Dynasty, and two people contributed the most, one was his younger brother Zhao Guangyi, and the other was Zhao Pu. Zhao Guangyi's opinion was very important whenever there was an important matter, for example, during the last year of Zhao Kuangyin's life, he was eager to move the capital to Luoyang, but after Zhao Guangyi opposed it, the matter was closed.
We can make a hypothesis, if Zhao Kuangyin dies, who can control the fortunes of the Great Song Dynasty between Zhao Guangyi and Zhao Dezhao? Obviously, Zhao Guangyi was superior. The ministers had always seen the wind at the helm, and when Zhao Kuangyin had not made Zhao Dezhao king, they had already sensed the direction of the wind in the Great Song Temple.
In addition, from the fifth dynasty to the beginning of the Song Dynasty, there was also a more bizarre rule, that is, once the prince was established, it was difficult for the emperor to be happy, "If you build a prince, the skin will be idle!" "Surrounded by strong enemies, once the crown prince is established, for the emperor, a second imperial court is arranged at his side, which greatly increases the risk of being overthrown." Finally, to sum up in one sentence, the meaning of Song Taizu's life to pass on the light and righteousness is very obvious.
References: History of the Song Dynasty, Zizhi Tongjian