hang ▁Ch ai ' s ▁conf ession , ▁the ▁two ▁e un uchs ▁had ▁promised ▁him ▁re wards ▁for ▁assault ing ▁the ▁crown ▁prince , ▁thus ▁indirect ly ▁imp lic ating ▁Lady ▁Zh eng ▁in ▁an ▁assass ination ▁plot . ▁Pres ented ▁with ▁inc rimin ating ▁evidence ▁and ▁the ▁gravity ▁of ▁the ▁accus ations , ▁the ▁W an li ▁Emperor , ▁in ▁an ▁attempt ▁to ▁spare ▁Lady ▁Zh eng , ▁personally ▁pres ided ▁over ▁the ▁case ▁and ▁laid ▁full ▁bl ame ▁on ▁the ▁two ▁e un uchs , ▁who ▁were ▁executed ▁along ▁with ▁Z hang ▁Ch ai . ▁Although ▁the ▁case ▁was ▁quickly ▁h ushed ▁up , ▁it ▁did ▁not ▁squ el ch ▁public ▁discuss ions ▁and ▁eventually ▁became ▁known ▁as ▁the ▁" Case ▁of ▁the ▁Palace ▁Ass ault " ▁( <0xE6> <0xA2> <0x83> 击 <0xE6> <0xA1> <0x88> ), ▁one ▁of ▁three ▁not orious ▁myster ies ▁of ▁the ▁late ▁M ing ▁dynast y . ▁ ▁In ▁ 1 6 1 5 , ▁the ▁crown ▁prince ▁became ▁inf uri ated ▁with ▁his ▁conc ub ine , ▁Lady ▁Li u , ▁who ▁was ▁the ▁mother ▁of ▁his ▁el dest ▁son , ▁the ▁future ▁Ch ong z hen ▁Emperor . ▁He ▁ordered ▁her ▁pun ished , ▁during ▁which ▁or de al ▁Lady ▁Li u ▁died . ▁It ▁is ▁deb ated ▁whether ▁the ▁crown ▁prince ▁ordered ▁her ▁to ▁be ▁killed ▁or ▁if ▁her ▁death ▁was ▁an ▁accident . ▁F ear ing ▁that ▁this ▁incident ▁would ▁further ▁turn ▁his ▁father ▁against ▁him ▁and ▁towards ▁Z hu ▁Ch ang