[Why] After Ming Taizu's death, Emperor Jianwen ascended and pushed iron-blooded vassal-reduction policy, forcing several royal clan princes to death in short order. This directly pushed the heavily armed Prince Yan Zhu Di to the dead end. [What] Zhu Di raised troops at Beiping under the high-held Jingnan banner of cleansing the emperor's flank, and waged a four-year tug-of-war with court forces. He finally avoided strong points and struck weakness, suddenly assaulting and capturing Nanjing, and Emperor Jianwen disappeared in the palace fire. [Who] Emperor Chengzu Zhu Di was a great prince of unmatched valor, leading from the front, and of supremely patient strategic wisdom, who later opened the Yongle prosperity. Emperor Jianwen Zhu Yunwen was weak and suspicious, trusted bookish scholars, and brought failure. [How] This bloody campaign transferred power to the Yongle branch, after which Chengzu moved the capital to Beijing, successfully shifting the empire's defense center of gravity north. It established the long-term political defense pattern of Ming.
Why
The historic event of Jingnan Campaign represents a key developmental peak of the Huaxia dynastic system. The shift of the imperial center of gravity to Beijing. By establishing this moral or administrative benchmark, it continues to shape the structural and philosophical fabric of ancient Chinese statecraft.