Joseon planned a regency for a boy king — and handed the throne to his uncle

King Munjong of Joseon, the son of Sejong the Great, reformed government and oversaw a flourishing court. When he fell ill in 1452 he knew his heir, the twelve-year-old Crown Prince Hongwi, would need protection. He arranged a regency led by his sister Princess Gyeonghye, Queen Dowager Jeongsun, and senior ministers, with the aim of guiding the boy until he came of age.

The plan assumed that the regents could hold the court together. It did not account for Munjong's younger brother, Grand Prince Suyang, an ambitious adult prince with his own network of officials and military officers. While the regents debated policy, Suyang gathered allies and waited.

In 1453 Suyang struck. His faction purged the leading regents and seized the gates of the palace. The young king was forced to abdicate; Suyang took the throne as King Sejo. The regency that had been designed to preserve the dynasty instead delivered it to a rival branch of the royal house.

Danjong was sent into exile and never returned to power. The coup, known as the Gyeyujeongnan, became a permanent warning in Korean political memory: a succession plan is only as strong as the power it leaves behind to enforce it.