There are many versions of the mystery of "the sound of candles and axes" in Song Dynasty.

One view is that Song Taizong "killed his brother in order to seize this position". People who hold this view believe that Song Taizu died suddenly in the sound of a candle shadow axe, while Song Taizong stayed in the Forbidden City that night and acceded to the throne in front of the coffin the next day. It's really hard to get rid of his brother. Cai Dongfan's Popular Romance of the History of Song Dynasty and Li Yihao's Romance of the Eighteen Dynasties of Song Palace both inherited and rendered the above statement, adding many details of Song Taizong's "killing his father". Another view is that Song Taizu's death has nothing to do with Song Taizong. Those who hold this view cite Sima Guang's Su Shui Ji to defend Song Taizong. According to "Shui Shui Ji", after Song Taizu's death, four drums were singing together. After the Song Dynasty, people were sent to the palace to call Zhao, the fourth son of Mao, but messengers were sent to Kaifeng. Zhao Guangyi was so frightened that he hesitated and dared not move forward. Urged by the messenger, he walked into the palace under the snow. Accordingly, when Emperor Taizong died, he was not in his bedroom, so it was impossible to "kill his brother". Bi Yuan's A Mirror of Sustainable Capital Management supports this statement. There is also a view that although Song Taizong is not sure that he is the murderer of his brother, he thinks he can't exonerate himself from taking the lead. In the process of Zhao Guangyi's accession to the throne, a series of abnormal phenomena did appear, that is, according to Su Shui Ji, Zhao Fangde, the king of Qin, was summoned after the Song Dynasty, but Zhao Guangyi entered the palace first, which caused a fait accompli. After the Song Dynasty, women saw that there was nothing they could do, so they had to call him "the housekeeper". The history of Song Taizong has also raised a series of questions: after Emperor Taizong ascended the throne, why didn't he change the nine-year treasure with only two months left into the first year of Taiping and the first year of rejuvenating the country in a hurry according to the practice of changing the yuan in the following year? Why did Emperor Taizong persecute his younger brother Zhao Tingmei again and again, and let him die of depression, since Du Taihou had an edict that "the throne was passed on to his younger brother"? After Emperor Taizong ascended the throne, why did Zhao Dezhao, the second son of Emperor Taizong, commit suicide? Emperor Taizong once named Huang Sao as the "treasure queen" after the Song Dynasty, but after her death, why not treat her funeral according to the queen's etiquette? All the above indications show that Song Taizong's accession to the throne is abnormal. How can future generations not doubt it?

Modern academic circles have basically affirmed that Song Taizu was indeed a sudden death, but there are some new theories about the specific cause of death. First, from a medical point of view, it is believed that Taizu died of manic depression inherited from his family. On the one hand, it is acknowledged that there is a deep contradiction between Taizong and Taizong, but it is considered that the "candle axe sound" incident is only an accidental emergency. The reason is that Emperor Taizong molested his favorite concubine, Mrs. Hua Rui, while people were sleeping, and was discovered by Emperor Taizong and angrily denounced. Taizong knew that he could not get his brother's forgiveness, so he killed him. Throughout the ages, all theories seem to be well-founded and reasonable. However, there is still no conclusive information about the cause of Song Taizu's death.