以子之矛，攻子之盾
yǐ zǐ zhī máo , gōng zǐ zhī dùn
lit. use sb's spear to attack his shield (idiom, derived from Han Feizi 韓非子|韩非子); turning a weapon against its owner
fig. to attack an opponent using his own devices; hoist with his own petard
yǐ zǐ zhī máo , gōng zǐ zhī dùn
lit. use sb's spear to attack his shield (idiom, derived from Han Feizi 韓非子|韩非子); turning a weapon against its owner
fig. to attack an opponent using his own devices; hoist with his own petard