Why is Kangxi's son named after Yin, and is there any rule or implication?

this is from the family. Many big families still have word generations. You can tell which generation it is from which word. Kangxi is the Xuan word generation, Yongzheng is the Yin word generation, Qianlong is the Hong word generation, from Japan (when Hong Li Hong Tian Hong, etc.), Jiaqing is the parallel word generation (note that it is not forever), from jade (Zhuanqi Zhuan, etc.) to Tongzhi Guangxu (these two peers) is the carrier word generation, from water. This is all about the family. Yin itself refers to the meaning of future generations. The words beside the complement mostly mean blessing or auspiciousness or sacrifice. For example, worshiping, worshiping, praying, and shooting.