The Battle of Ruxu, also known as the Battle of Ruxukou, was fought between the warlords Sun Quan and Cao Cao in 217 in the late Eastern Han dynasty. Two years earlier, Sun Quan attempted to take control of Hefei fortress, but failed due to a sudden plague and the staunch resistance put up by Cao Cao's forces under Zhang Liao. Since then, Cao Cao had been making preparations for a counterattack on Sun Quan, and he personally led his navy to Ruxu to fight a decisive battle. This battle is not to be confused with another earlier battle that also took place at Ruxu in 213.