Case of Duchess Nanzi's Licentiousness and Crown Prince Kuaikui's Attempted Assassination Leading to Exile

In the State of Wei during the Spring and Autumn period, Duchess Nanzi, wife of Duke Ling, engaged in a notorious affair with Song Chao, a noble from the State of Song. Duke Ling tacitly permitted this relationship. Crown Prince Kuaikui, while on a diplomatic mission to Song, was humiliated by mocking songs about Nanzi. Enraged and ashamed, he conspired with his retainer Xi Yangsu to assassinate Nanzi during a court audience. However, Xi Yangsu lost his nerve and failed to act. Nanzi detected the plot, cried out, and revealed the attempt to Duke Ling. The duke pursued Kuaikui, who fled first to Song and then to Jin, triggering a prolonged succession crisis.

There was no formal trial. Kuaikui was forced into exile, and his son Zhe was installed as heir and later ruled as Duke Chu of Wei. Years later, with Jin state support, Kuaikui returned and deposed his own son, reigning as Duke Zhuang. This father-son conflict over the throne lasted over a decade.

The central disputes revolved around the conflict between filial piety and justice: whether a son could justifiably kill his father's wife to preserve family honor, and whether Duke Ling's protection of an adulterous spouse over his own heir violated moral and political order. The case highlighted deep tensions between personal virtue, patriarchal authority, and state stability.

The case became a emblematic moral crisis of the decaying Zhou feudal order. It deeply influenced Confucian thought on the rectification of names (zhengming), as Confucius was consulted about the succession struggle and emphasized that proper titles and relationships must govern political legitimacy. The episode was cited for generations as a cautionary tale of how private vice and failed filial duty could unravel a state.