a　leader　of　armies。

〃But　what　should　a　leader　be　like？〃　asked　Cao　Cao。

〃He　should　be　endued　with　firmness　and　courage；　never　turn　aside　from　a　difficulty；　but　be　in　the　van　of　his　officers　and　troops。　Rewards　should　be　certain；　and　so　should　punishments。〃

Cao　Cao　smiled　with　pleasure。

In　the　twenty…third　year　of　Rebuilt　Tranquillity　（AD　218）；　the　Wuhuan　Peoples　revolted　in　Daichun；　and　Cao　Cao　sent　this　son　with　fifty　thousand　troops　to　suppress　them。　Just　as　Cao　Zhang　was　leaving；　his　father　read　him　a　homily　on　his　duty。

〃At　home　we　are　father　and　son；　but　when　a　task　is　given　you；　you　have　to　consider　your　duty　as　a　servant　of　your　ruler。　The　law　knows　no　kindness；　and　you　must　beware。〃

When　the　expedition　reached　the　north　of　Daichun；　Cao　Zhang　led　the　array　and　smote　as　far　as　Sanggan　in　the　Gobi　Dese