What does "entering the customs" mean? See below.

Facing the northeast, "Shanhaiguan" is "Shanhaiguan". Crossing the Great Wall and entering Shanhaiguan means entering the "Central Plains" and then ruling all of China. Therefore, some documents in the Qing Dynasty say that "entering the customs" means obtaining sovereignty instead of the Ming Dynasty.

Before that, there were two stages, namely, the "late Jin" written by the Qing Taizu Nurhachi (actually called "Jin" at that time, and "late Jin" was named by later historians to distinguish the "Jin" in the Song Dynasty). The capital was first in Hetuala-Xingjing, then moved to Liaoyang-Tokyo, and then moved to Shenyang-Shengjing.

His son, Huang Taiji, thought that the name "Jin" was easy to arouse the resentment of the Han nationality, so he changed his name to "Qing" (but it actually meant to replace it, because unofficial history said that taking "Qing" meant a glorious dynasty in it. In the 24 solar terms, "Qing" means that "Qing" comes first and "Ming" comes last ...) The capital is still in Shengjing, that is, Shenyang.