The so-called "nine sons seize the throne" refers to the nine sons of Kangxi competing for the throne. These nine sons are: the eldest elder brother Yinzhen, the second elder brother Yinzhen (formerly the prince), the third elder brother Yinzhi, the fourth elder brother Yinzhen (the later emperor Yongzheng), the eighth elder brother Yinzhen, the ninth elder brother Yinzhen, the tenth elder brother Yinzhen (礻我), the thirteenth elder brother Yinxiang, and the fourteenth elder brother Yinzhen.