ated　repeatedly；　and　his　two　Van　Leaders　were　slain。　Further；　his　Qiang　allies　have　suffered　great　loss。　Cao　Zhen　is　sending　for　help；　and　the　case　is　very　urgent。〃

Cao　Rui　was　alarmed　and　asked　for　someone　to　say　how　to　drive　off　the　victorious　foe。

Thereupon　Hua　Xin　said；　〃It　will　be　necessary　for　Your　Majesty　to　go　in　person。　You　should　call　together　all　the　nobles；　and　each　will　have　to　exert　himself。　Unless　this　is　done；　Capital　Changan　will　be　lost　and　the　whole　Land　Within　the　Passes　be　in　danger。〃

But　Imperial　Guardian　Zhong　Yao　opposed　him。

Said　he；　〃The　knowledge　of　every　leader　must　exceed　that　of　those　led；　then　only　will　he　be　able　to　control　them。　Sun　Zi　the　Strategist　sums　it　up　very　briefly：　'Know　the　enemy；　know　thyself；　and　every　battle　is　a　victory。'　I　know　Cao　Zhen　has　had　great　experience　in　the　field；　but　he　is　n