In the late 1970s, the People's Republic of China (PRC) and North Korea arrived at contradictory answers regarding the question of succession, testing the strength of bilateral ties at a complex moment in the two countries’ domestic politics and in the Cold War. Blaming the excesses of Maoist radicalism on “feudal thinking,” Deng Xiaoping launched a campaign in the summer of 1980 to “eliminate feudalism” from the Chinese Communist Party and elevate a new generation of leaders. Just a few months later, at the Sixth Congress of the Korean Workers’ Party, Kim Il Sung went public with what Deng saw as the ultimate “feudal” act: a plan to pass down the role of Supreme Leader to his eldest son, Kim Jong Il. By scrutinizing the public record and secret transcripts of Sino-Korean diplomacy, this article traces the origins of their contradictory approaches to political succession and the evolution of Deng's response to Kim's plan from disapproval to acquiescence.