▁It ▁could ▁refer ▁to ▁the ▁capital ▁of ▁the ▁em peror ▁to ▁distinguish ▁it ▁from ▁the ▁capit als ▁of ▁his ▁v ass als , ▁as ▁in ▁Western ▁Z hou . ▁It ▁could ▁refer ▁to ▁the ▁states ▁of ▁the ▁Central ▁P lain ▁to ▁distinguish ▁them ▁from ▁states ▁in ▁outer ▁regions . ▁During ▁the ▁Han ▁dynast y , ▁three ▁us ages ▁of ▁" Z h ong gu o " ▁were ▁common . ▁The ▁Sh i ▁J ing ▁explicitly ▁defines ▁" Z h ong gu o " ▁as ▁the ▁capital ; ▁the ▁Records ▁of ▁the ▁Grand ▁Histor ian ▁uses ▁the ▁concept ▁z h ong ▁to ▁indicate ▁the ▁center ▁of ▁civil ization : ▁" E ight ▁famous ▁mountains ▁are ▁there ▁in ▁T ian x ia . ▁Three ▁are ▁in ▁Man ▁and ▁Y i . ▁Five ▁are ▁in ▁Zh ō ng hu á ." ▁The ▁Records ▁of ▁the ▁Three ▁Kingdom s ▁uses ▁the ▁concept ▁of ▁the ▁central ▁states ▁in ▁" Z h ō ng hu á ", ▁or ▁the ▁states ▁in ▁" Z h ō ng hu á " ▁which ▁is ▁the ▁center , ▁depending ▁on ▁the ▁interpretation . ▁It ▁records ▁the ▁following ▁ex h ort ation : ▁" If ▁we ▁can ▁lead ▁the ▁host ▁of ▁Wu ▁and ▁Y ue ▁to ▁opp ose ▁" Z h ong gu o ," ▁then ▁let ▁us ▁break ▁off ▁relations ▁with ▁them ▁soon ." ▁In ▁this ▁sense , ▁the ▁term ▁" Z h ong gu o " ▁is ▁syn onymous ▁with ▁Zh ō ng hu á ▁( /) ▁and ▁Hu á xi à