s；　and　both　sides　encamped。

〃Xu　Zi　is　very　formidable。　How　can　we　overe　him？〃　asked　Jiang　Wei。

〃Tomorrow　make　pretense　of　defeat　and　so　draw　them　into　an　ambush；〃　replied　Xiahou　Ba。

〃But　remember　whose　son　this　Sima　Zhao　is；〃　said　Jiang　Wei。　〃Sima　Zhao　cannot　be　a　novice　in　war。　If　he　sees　a　likely　spot　for　an　ambush；　he　will　halt。　Now　the　troops　of　Wei　have　cut　our　transportation　many　times。　Let　us　do　the　same　to　them；　and　we　may　slay　this　Xu　Zi。〃

He　called　in　Liao　Hua　and　Zhang　Yi　and　gave　them　secret　orders；　sending　them　in　different　directions。　Then　he　laid　iron　thorns　along　all　the　approaches　and　planted　thorny　barriers　as　if　making　a　permanent　defense。　When　the　troops　of　Wei　came　up　and　challenged；　the　troops　of　Shu　refused　battle。

The　scouts　reported　to　Sima　Zhao：　〃The　Shu　supplies　are　ing　up　along　the　rear　of　Iron　Cage　Mountain；　and　they　are　using　the　wooden　oxen　and　running　horses　as　transport。　The　Shu　army　are　building　permanent　defenses　and　are　awaiting　the　arrival　of　their　allies　the　Qiang　tribes。〃

Then　said　Sima　Zhao　to　Xu　Zi；　〃We　formerly　defeated　the　army　of　Shu　by　cutting　off　supplies；　and　we　can　do　that　again。　Let　five　thousand　troops　go　out　tonight　and　occupy　the　road。〃

About　the　middle　of　the　first　watch　Xu　Zi　marched　across　the　hills。　When　he　came　to　the　other　side；　he　saw　a　couple　of　hundred　soldiers　driving　a　hundred　or　so　heads　of　mechanical　animals　laden　with　grain　and　forage。　His　army　rushed　down　upon　them　with　shouts；　and　the　troops　of　Shu；　seeing　that　their　road　was　impassable；　abandoned　their　supplies　and　ran　away。　Xu　Zi　took　possession　of　the　supply　train；　which　he　sent　back　to　his　own　camp　under　the　escort　of　half　his　troops。　With　the　other　half　he　set　out　in　pursuit。

About　three　miles