This is not because Li Shimin cares about his father and son, but because Li Yuan, as the founding emperor, not only has many die-hard fans, but also has the function of calming the situation. Although Li Shimin decided to kill the Prince and Li Yuanji, the king of Qi, it did not mean that the consequences could be controlled.
Therefore, whether as a temporary father or as a mascot puppet, Li Yuan must live and give Li Shimin legitimacy. This is why Weichi Gong Pi saw that Zhirui led his men into the palace to force Tang Gaozu to order, announced the rebellion of the Prince, and handed over the power of the world's military forces to Li Shimin. At the same time, within a few days of the Xuanwumen Revolution, the core members of Li Shimin Group mastered the key departments of the imperial court and made Tang Gaozu a prince through imperial edict. When everything was ready, two months after the change of Xuanwu Gate, Tang Gaozu abdicated as the emperor's father, and Li Shimin officially ascended the throne.
This time, Li Shimin breathed a sigh of relief, and his father was no longer a threat. At this point, it is not important to kill or not. And it is nothing more than fighting for power and profit, not threatening to raise it, there is no need to fight. It can be seen that ruthlessness is the relationship between the emperor and the country, the affection between father and son and the righteousness of brothers are secondary, and the core is the power game. Tang Gaozu can be said to be the most humbled of the founding emperors in ancient China, and Li Shimin can also be said to be the most meticulous court coup.
However, Li Shimin, the emperor Taizong who created the prosperous time of Zhenguan, won the praise of later generations with his good reputation and became a historical delicacy.