According to the historical website, "Northern China merged into Sanjin" was a political slogan put forward by Zhang Yi, a statesman of Wei State in the Warring States Period in ancient China. Among them, the "Northern Expedition" means that Wei wants to annex Cai in the north to expand his territory; "Rejecting the Three Jin Dynasties" means that Wei wants to defeat the three eastern countries-Zhao, South Korea and Yan, so as to consolidate his position.

This slogan reflected Wei's political ambition and desire for expansion at that time, and it was also an important manifestation of the hegemony of various countries during the Warring States period.

Disclaimer, the above contents are for reference only, please don't be blindly superstitious.