Mencius claims no truly just wars occurred in the Spring and Autumn age, though some rulers acted less brutally. Only the Son of Heaven held the right to launch punitive campaigns; equal states had no authority to attack one another.
Historically, Cao Cao carried out two large-scale massacres in Xuzhou. The first occurred in 193. According to According to Romance of the Three Kingdoms, when his father was killed by a general under the command of Tao Qian, the governor of Xuzhou, Cao Cao led his army to attack Tao Qian, capturing over ten…