After returning to his camp,Ts'ao Ts'ao blamed Ts'ai Mao and Chang Yun for the defeat.Ts'ai Mao explained,"The soldiers from Chingchou City have not been well trained and the soldiers from north China have no experience on the water.Now we must defend our camp and train the soldiers from north China together with the soldiers from Chingchou City.When they all become good at naval battles,we can renew our attack on the enemy."Ts'ao Ts'ao then appointed Ts'ai Mao and Chang Yun to take charge of the training of his navy.